Ultraviolet ray curable ink composition for use in ink jet method and printed object

ABSTRACT

An ultraviolet ray curable ink composition adapted to be ejected by using an ink jet method is provided. The ultraviolet ray curable ink composition includes a polymerizable compound and metal powder. The metal powder is constituted from metal particles subjected to a surface treatment with a fluorine type silane compound and/or a fluorine type phosphoric acid ester as a surface treatment agent. A polymerizable compound includes a monomer having an alicyclic structure. This makes it possible to provide the ultraviolet ray curable ink composition which has excellent storage stability, can provide excellent dispersion stability of the metal particles of the metal powder. A printed object is also provided. Such a printed object is produced by using the ultraviolet ray curable ink composition.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims a priority from a JapanesePatent Application No. 2012-264695 filed on Dec. 3, 2012, which ishereby expressly incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to an ultraviolet ray curable inkcomposition for use in an ink jet method (hereinafter, simply referredto as “ultraviolet ray curable ink composition”) and a printed object.

2. Related Art

Conventionally, as a method of manufacturing a trinket showing anappearance having gloss, used is a metal plating, a metal foil pressprinting using a metal foil, a thermal transfer using a metal foil orthe like.

However, there are problems in that a fine pattern is hardly to beformed by using such methods or such methods are difficult to be usedfor a curved surface portion. Furthermore, the metal foil press printingis difficult to achieve on-demand printing, so that there are problemsin that it is difficult to supply various kinds of print materials or itis difficult to form metal-texture printing having gradation.

On the other hand, as a method of recording a composition containing apigment or a dye onto a recording medium, used is a method of recordingthe composition using an ink jet method. The ink jet method has suchadvantages as to be able to form the fine pattern or to be used for thecurved surface portion. Further, in order to further improve wearresistance, water resistance, solvent resistance and the like of aprinted portion, recently, a composition (ultraviolet ray curable inkcomposition), which includes a polymerizable compound and can be cureddue to ultraviolet ray irradiation, is used in the ink jet method (forexample, Patent document 1).

However, in the case where metal particles of metal powder are usedinstead of the pigment or the dye in the ultraviolet ray curable inkcomposition, there is a problem in that it is difficult to sufficientlyexhibit properties such as gloss provided inherently by the metal. Inaddition, stability (storage stability) of the composition is lowered.This causes a problem in that the composition is turned into a gel, andthus ejection stability of the composition is lowered due to viscosityincrease thereof.

The Patent Document 1 is JP-A 2009-57548 which is an example of relatedart.

SUMMARY

Accordingly, it is an object of the present invention to provide anultraviolet ray curable ink composition which has excellent storagestability, can provide excellent dispersion stability of metal particlesof metal powder, and can be reliably used for producing a pattern(printed portion) having high gloss and excellent wear resistance.Furthermore, it is another object of the present invention to provide aprinted object having such a pattern having high gloss and excellentwear resistance produced by using the ultraviolet ray curable inkcomposition.

These objects are achieved by the present inventions described below.

An ultraviolet ray curable ink composition adapted to be ejected byusing an ink jet method of the invention, comprises:

a polymerizable compound;

metal powder; and

wherein the metal powder is constituted from metal particles subjectedto a surface treatment with a fluorine type silane compound and/or afluorine type phosphoric acid ester as a surface treatment agent, and

wherein the polymerizable compound includes a monomer having analicyclic structure.

This makes it possible to provide the ultraviolet ray curable inkcomposition which has excellent storage stability, can provide excellentdispersion stability of the metal particles of the metal powder, and canbe reliably used for producing a pattern (printed portion) having highgloss and excellent wear resistance.

In the ultraviolet ray curable ink composition of the invention, it ispreferred that an amount of the monomer having the alicyclic structurecontained in the ultraviolet ray curable ink composition is in the rangeof 40 mass % or more but 90 mass % or less.

This makes it possible to improve dispersion stability of the metalparticles of the metal powder especially, and obtain excellent injectionstability of the ultraviolet ray curable ink composition for a longperiod of time. In particular, even if the ultraviolet ray curable inkcomposition does not contain a dispersant, it is possible to obtain theexcellent effects as described above.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that each of the metal particles of the metal powder isconstituted from a base particle and Al constituting at least a surfaceof the base particle, and the metal particle is subjected to the surfacetreatment with the fluorine type silane compound and/or the fluorinetype phosphoric acid ester.

Al inherently shows especially excellent gloss among various kinds ofmetal materials. However, in the case where powder constituted fromparticles formed from Al is used in an ultraviolet ray curable inkcomposition, the present inventors have found that storage stability ofthe ultraviolet ray curable ink composition becomes particularly low,the ultraviolet ray curable ink composition is turned into a gel, andtherefore the problems such as lowering of ejection stability of theultraviolet ray curable ink composition due to viscosity increasethereof occur more remarkably. On the other hand, even if the powderconstituted from the particles of which surfaces are constituted of Alis used in the invention, it is possible to reliably prevent theproblems as described above from occurring. Specifically, in the metalpowder constituting the ultraviolet ray curable ink composition, themetal particles, of which at least surfaces are constituted of Al as amain component thereof, of the metal powder are subjected to a surfacetreatment with a fluorine type silane compound and/or a fluorine typephosphoric acid ester. This makes it possible to exhibit the effects ofthe invention conspicuously.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that each of the metal particles of the metal powder isof a scaly shape.

This makes it possible to improve the gloss and wear resistance of theprinted portion of the printed object produced by using the ultravioletray curable ink composition especially.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that when the metal particles of the metal powder aresubjected to the surface treatment with the fluorine type silanecompound, the fluorine type silane compound has a chemical structurerepresented by the following formula (1):

R¹SiX¹ _(a)R² _((3−a))  (1)

where in the above formula (1), “R¹” represents a hydrocarbon group inwhich a part or all of hydrogen atoms are substituted with fluorineatoms, “X¹” represents a hydrolysis group, an ether group, a chlorogroup or a hydroxyl group, “R²” represents an alkyl group having acarbon number in the range of 1 or more but 4 or less, and “a” is anintegral number in the range of 1 or more but 3 or less.

This makes it possible to improve the storage stability of theultraviolet ray curable ink composition especially, and the gloss andwear resistance of the printed portion of the printed object produced byusing the ultraviolet ray curable ink composition.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that when the metal particles of the metal powder aresubjected to the surface treatment with the fluorine type phosphoricacid ester, the fluorine type phosphoric acid ester has a chemicalstructure represented by the following formula (2):

POR_(n)(OH)_(3-n)  (2)

where in the above formula (2), “R” is CF₃(CF₂)_(m)—,CF₃(CF₂)_(m)(CH₂)_(l)—, CF₃(CF₂)_(m)(CH₂O)_(l)—,CF₃(CF₂)_(m)(CH₂CH₂O)_(l)—, CF₃(CF₂)_(m)O— or CF₃(CF₂)_(m)(CH₂)_(l)O—,“n” is an integral number in the range of 1 or more but 3 or less, “m”is an integral number in the range of 5 or more but 17 or less, and “l”is an integral number in the range of 1 or more but 12 or less.

This makes it possible to improve the storage stability of theultraviolet ray curable ink composition especially, and the gloss andthe wear resistance of the printed portion of the printed objectproduced by using the ultraviolet ray curable ink composition.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that when the metal particles of the metal powder aresubjected to the surface treatment with the fluorine type phosphoricacid ester, the fluorine type phosphoric acid ester is represented byCF₃(CF₂)₅(CH₂)₂O(P)(OH)₂ and/or CF₃(CF₂)₅(CH₂)₂O(P)(OH)(OCH₂CH₃).

This ensures that the metal particles of the metal powder are subjectedto the surface treatment reliably and sufficiently. As a result, it ispossible to improve chemical stability and dispersion stability of themetal particles of the metal powder in the ultraviolet ray curable inkcomposition and make the storage stability and the ejection stabilityfor a long period of time of the ultraviolet ray curable ink compositionexcellent. Further, in the printed object produced by using theultraviolet ray curable ink composition, it is possible to reliablyarrange the metal particles of the metal powder at the vicinity of anouter surface of the printed portion, so that it is possible toefficiently exhibit characteristics such as the gloss which areinherently possessed by a metal material of the metal particlesconstituting the metal powder. Further, even if a polymerizable compoundhaving low surface tension is used as a constituent material of theultraviolet ray curable ink composition, it is possible to reliablyarrange the metal particles of the metal powder at the vicinity of theouter surface of the printed portion in the printed object produced byusing the ultraviolet ray curable ink composition. Consequently, it ispossible to efficiently exhibit the characteristics such as the glosswhich are inherently possessed by the metal material of the metalparticles constituting the metal powder.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that an average particle size of the metal particles ofthe metal powder is in the range of 500 nm or more but 3.0 μm or less.

This makes it possible to further improve the gloss and high-grade senseof the printed object to be produced by using the ultraviolet raycurable ink composition. Furthermore, it is possible to further improvethe storage stability and the ejection stability of the ultraviolet raycurable ink composition.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that the monomer having the alicyclic structure includesa monofunctional monomer having a hetero atom in the alicyclicstructure.

This makes it possible to improve the dispersion stability of metalparticles of metal powder, and therefore obtain the excellent ejectionstability of the ultraviolet ray curable ink composition for a longperiod of time. In particular, even if the ultraviolet ray curable inkcomposition does not contain a dispersant, the excellent effects asdescribed above are obtained.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that an amount of the monofunctional monomer contained inthe ultraviolet ray curable ink composition is in the range of 10 mass %or more but 80 mass % or less.

This makes it possible to suppress cure shrinkage of the ultraviolet raycurable ink composition, thereby reliably obtaining the ultraviolet raycurable ink composition in which the metal particles are scattered in asmall amount thereof. Consequently, it is possible to reliably use theultraviolet ray curable ink composition for producing the printed objectprovided with the pattern (printed portion) having excellent gloss.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that the monomer having the alicyclic structure includesone or more selected from the group consisting of tris(2-acryloyloxyethyl) isocyanurate, dicyclopentenyl oxyethyl acrylate, adamantylacrylate, γ-butyrolactone acrylate, N-vinyl caprolactam, N-vinylpyrrolidone, pentamethyl piperidyl acrylate, tetramethyl piperidylacrylate, 2-methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl acrylate,mevalonic acid lactone acrylate, dimethylol tricyclodecane diacrylate,dimethylol dicyclopentane diacrylate, dicyclopentenyl acrylate,dicyclopentanyl acrylate, isobornyl acrylate, cyclohexyl acrylate,acryloyl morpholine and tetrahydrofurfuryl acrylate.

This makes it possible to further improve the gloss and high-grade senseof the printed object to be produced by using the ultraviolet raycurable ink composition. Furthermore, it is possible to further improvethe storage stability and the ejection stability of the ultraviolet raycurable ink composition.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that the polymerizable compound includes one or moreselected from the group consisting of phenoxy ethyl acrylate,2-(2-vinyloxy ethoxy) ethyl acrylate, dipropylene glycol diacrylate,tripropylene glycol diacrylate, 2-hydroxy-3-phenoxy propyl acrylate and4-hydroxy butyl acrylate in other than the monomer having the alicyclicstructure.

This makes it possible to especially improve the storage stability andthe ejection stability of the ultraviolet ray curable ink composition,and to make reactivity of the ultraviolet ray curable ink compositionejected by the ink jet method more excellent. This makes it possible tofurther improve productivity of the printed object and the wearresistance and the like of the pattern to be formed.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that the ultraviolet ray curable ink composition furthercomprises a substance A having a partial structure represented by thefollowing formula (5),

where in the formula (5), “R¹” is an oxygen atom, a hydrogen atom, ahydrocarbon group or an alkoxyl group, and each of “R²”, “R³”, “R⁴” and“R⁵” is independently a hydrogen atom or a hydrocarbon group.

This makes it possible to further improve the storage stability andcuring property of the ultraviolet ray curable ink compositionespecially. Furthermore, it is possible to effectively exhibit the glossand the high-grade sense provided inherently by a metal materialconstituting the metal particles of the metal powder in the printedobject to be produced by using the ultraviolet ray curable inkcomposition, so that it is possible to especially improve the gloss andthe wear resistance of the printed portion. Consequently, it is possibleto especially improve durability of the printed object.

In the ultraviolet ray curable ink composition of the invention, it isalso preferred that when an amount of the substance A is defined asX_(A) mass % and an amount of the metal powder is defined as X_(M) mass%, the following relation is satisfied: 0.01≦X_(A)/X_(M)≦0.8.

This makes it possible to further improve the storage stability and theejection stability of the ultraviolet ray curable ink compositionespecially. Furthermore, it is possible to further improve the gloss andhigh-grade sense of the printed portion of the printed object to beproduced by using the ultraviolet ray curable ink composition.

A printed object of the invention is produced by applying theultraviolet ray curable ink composition described above onto a recordingmedium, and then irradiating the ultraviolet ray curable ink compositionwith an ultraviolet ray.

This makes it possible to provide the printed object including thepattern (printed portion) having excellent gloss and excellent wearresistance.

DESCRIPTION OF EXEMPLARY EMBODIMENT

Hereinbelow, preferred embodiments of the invention will be described indetail.

Ultraviolet ray curable ink composition

First, an ultraviolet ray curable ink composition for use in an ink jetmethod (hereinafter, simply referred to as “ultraviolet ray curable inkcomposition”) of the invention will be described.

The ultraviolet ray curable ink composition of the invention is adaptedto be ejected using the ink jet method and includes a polymerizablecompound which is polymerized by irradiating with an ultraviolet ray.

Meanwhile, conventionally, as a method of manufacturing a trinketshowing an appearance having gloss, used is a metal plating, a metalfoil press printing using a metal foil, a thermal transfer using a metalfoil or the like.

However, there are problems in that a fine pattern is hardly to beformed by using such methods or such methods are difficult to be usedwith respect to a curved surface portion. Further, there is also aproblem in that the use of the metal foil press printing cannot form ametal-texture printing having a gradation.

On the other hand, as a method of recording a composition containing apigment or a dye onto a recording medium, used is a method of recordingthe composition using an ink jet method. The ink jet method has suchadvantages as to be able to form the fine pattern or to be used withrespect to the curved surface portion. Further, in order to furtherimprove wear resistance, water resistance, solvent resistance and thelike of a printed portion, recently, a composition (ultraviolet raycurable ink composition), which includes a polymerizable compound andcan be cured due to ultraviolet ray irradiation, is used in the ink jetmethod.

However, in the case where metal powder are used instead of the pigmentor the dye in the ultraviolet ray curable ink composition, there is aproblem in that it is difficult to sufficiently exhibit properties suchas gloss provided inherently by the metal. In addition, stability(storage stability) of the composition is lowered. This causes a problemin that the composition is tuned into a gel, and thus ejection stabilityand the like of the composition is lowered due to viscosity increasethereof.

Accordingly, the present inventors have earnestly conducted studies fora purpose of solving the above problems. As a result, they have foundthe invention. In other words, the ultraviolet ray curable inkcomposition of the invention contains a monomer having an alicyclicstructure as the polymerizable compound in addition to metal powder.Metal particles of the metal powder are subjected to a surface treatmentwith a fluorine type silane compound and/or a fluorine type phosphoricacid ester as a surface treatment agent. Even if an amount of adispersant contained in the ultraviolet ray curable ink composition islow or the ultraviolet ray curable ink composition contains nodispersant, it is possible to improve chemical stability and dispersionstability of the metal particles of the metal powder in the ultravioletray curable ink composition and make the storage stability and theejection stability for a long period of time of the ultraviolet raycurable ink composition excellent. Further, it is possible to reliablyarrange the metal particles of the metal powder at the vicinity of anouter surface of a printed portion in a printed object produced by usingthe ultraviolet ray curable ink composition. Consequently, it ispossible to efficiently exhibit characteristics such as gloss which areinherently possessed by a metal material of the metal particlesconstituting the metal powder.

In the invention, the alicyclic structure means a cyclic structurehaving no aromatic property (pi-conjugated system), which includes ahetero atom as a constituent atom in addition to the cyclic structureformed of only carbon atoms. Further, the monomer having the alicyclicstructure has only to such an alicyclic structure. In addition to that,the monomer may be provided with a cyclic structure having an aromaticproperty (cyclic structure having pi-conjugated system).

Metal Powder

As described above, the ultraviolet ray curable ink composition of theinvention contains the metal particles which are subjected to thesurface treatment with the fluorine type silane compound and/or thefluorine type phosphoric acid ester as the surface treatment agent asthe metal powder.

Base Particles

First, description will be made on base particles constituting the metalparticles (particles to be subjected to the surface treatment with thesurface treatment agent).

Each of the base particles constituting the metal particles may beconstituted of a metal material in an area including at least thevicinity of a surface thereof. For example, the whole of the baseparticle may be constituted of the metal material. Alternatively, thebase particle may be constituted from a base portion constituted of anon-metal material and a coated layer constituted of the metal materialcoating the base portion.

Further, examples of the metal material constituting the base particlesincluded a metal as a simple substance, various kinds of alloys and thelike. It is preferred that the base particles are constituted of Al inat least the vicinity of the surfaces thereof mainly. Al inherentlyshows especially excellent gloss among various kinds of metal materials.However, in the case where powder constituted from particles formed fromAl is used in an ultraviolet ray curable ink composition, the presentinventors have found that storage stability of the ultraviolet raycurable ink composition becomes particularly low, the ultraviolet raycurable ink composition is turned into a gel, and therefore the problemssuch as lowering of ejection stability of the ultraviolet ray curableink composition due to viscosity increase thereof occur more remarkably.On the other hand, even if the powder constituted from the particles ofwhich surfaces are constituted of Al is used in the invention, it ispossible to reliably prevent the problems as described above fromoccurring. Specifically, in the metal powder constituting theultraviolet ray curable ink composition, the metal particles, of whichat least surfaces are constituted of Al as a main component thereof, aresubjected to the surface treatment with the surface treatment agent (thefluorine type silane compound and/or the fluorine type phosphoric acidester). This makes it possible to exhibit the effects of the inventionconspicuously.

Further, the base particles may be produced by using any methods. In thecase where at least the surfaces of the base particles are formed fromAl, it is preferred that they are produced by forming a film made of Alon each particle by using a vapor phase film formation method, and thencrushing the film. This makes it possible to more effectively expressthe gloss and the like which Al inherently has in the pattern (printedportion) formed by using the ultraviolet ray curable ink composition ofthe invention. Further, this also makes it possible to suppressvariation among the base particles in property. Furthermore, by usingsuch a method, it is possible to appropriately produce even relativelyfine base particles.

In the case where the base particles are produced by using such amethod, for example, by forming (film-forming) the film made of Al ontoa base material (base), it is possible to appropriately produce the baseparticles. As the base material, for example, a plastic film such aspolyethylene terephthalate can be used. Further, the base material mayhave a release agent layer provided on a film-formation surface thereof.

Furthermore, it is preferred that the crushing is carried out bysubjecting the film to ultrasonic vibration in a liquid. This makes itpossible to easily and reliably obtain the base particles having theparticle size as described above and to suppress variation of theparticles in a size, a shape and property from occurring.

Further, in the case where the crushing is carried out in the abovemethod, as the above mentioned liquid, it is preferable to use: alcoholssuch as methanol, ethanol, propanol and butanol; hydrocarbon-basedcompounds such as n-heptane, n-octane, decane, dodecane, tetradecane,toluene, xylene, cymene, durene, indene, dipentene, tetrahydronaphthalene, decahydro naphthalene and cyclohexyl benzene; ether-basedcompounds such as ethylene glycol dimethyl ether, ethylene glycoldiethyl ether, ethylene glycol methyl ethyl ether, diethylene glycoldimethyl ether, diethylene glycol diethyl ether, diethylene glycolmethyl ethyl ether, diethylene glycol monobutyl ether acetate,diethylene glycol n-butyl ether, tripropylene glycol dimethyl ether,triethylene glycol diethyl ether, 1,2-dimethoxy ethane, bis(2-methoxyethyl)ether and p-dioxane; polar compounds such as propylene carbonate,γ-butyrolactone, N-methyl-2-pyrolidone, N,N-dimethyl formamide (DMF),N,N-dimethyl acetamide (DMA), dimethyl sulfoxide, cyclohexanone andacetonitrile; and the like. By using such a liquid, it is possible toprevent undesirable oxidation and the like of the base particles and tofurther improve productivity of the base particles and the metalparticles of the metal powder. Further, it is also possible to make thevariation of the particles in the size, the shape and the propertysmaller.

Surface Treatment Agent

As described above, the metal particles of the metal powder according tothe invention are subjected to the surface treatment with the fluorinetype silane compound and/or the fluorine type phosphoric acid ester asthe surface treatment agent.

First, description will be made on the fluorine type silane compound inthe surface treatment agent.

Examples of the fluorine type silane compound include a silane compoundhaving at least one fluorine atom in a molecule thereof.

As the fluorine type silane compound as the surface treatment agent, acompound having a chemical structure represented by the followingformula (1) is especially preferable.

R¹SiX¹ _(a)R² _((3−a))  (1)

In the above formula (1), “R¹” is a hydrocarbon group in which a part ofhydrogen atoms or all hydrogen atoms are substituted with fluorineatom(s), “X¹” is a hydrolysable group, an ether group, a chloro group ora hydroxyl group, “R²” is an alkyl group having carbon numbers in therange of 1 or more but 4 or less, and “a” is an integral number of 1 ormore but 3 or less.

This makes it possible to improve the storage stability of theultraviolet ray curable ink composition especially, and the gloss andthe wear resistance of the printed portion of the printed objectproduced by using the ultraviolet ray curable ink composition.

Examples of “R¹” in the above formula (1) include an alkyl group, analkenyl group, an aryl group, an aralkyl group and the like in which apart of hydrogen atoms or all hydrogen atoms are substituted with thefluorine atom(s). Further, at least a part of hydrogen atoms containedin a molecular structure of each of such groups (that is, hydrogen atomsnot substituted with the fluorine atoms) may be substituted with anamino group, a carboxyl group, a hydroxyl group, a thiol group or thelike. Furthermore, a carbon chain contained in each of the above groupsmay include a hetero atom such as —O—, —S—, —NH— or —N═ or an aromaticring such as benzene in a middle thereof. Concrete examples of “R¹”include a phenyl group, a benzyl group, a phenethyl group, a hydroxyphenyl group, a chloro phenyl group, an amino phenyl group, a naphthylgroup, an anthranyl group, a pyrenyl group, a thienyl group, a pyrrolylgroup, a cyclohexyl group, a cyclohexenyl group, a cyclopentyl group, acyclopentenyl group, a pyridinyl group, a methyl group, an ethyl group,a n-propyl group, an isopropyl group, a n-butyl group, an isobutylgroup, a sec-butyl group, a tert-butyl group, an octadecyl group, an-octyl group, a chloro methyl group, a methoxy ethyl group, a hydroxyethyl group, an amino ethyl group, a cyano group, a mercapto propylgroup, a vinyl group, an allyl group, an acryloxy ethyl group, amethacryloxy ethyl group, a glycidoxy propyl group, an acetoxy group andthe like, in which a part of the hydrogen atoms or all hydrogen atomsare substituted with the fluorine atom(s).

Examples of the fluorine type silane compound represented by the formula(1) include a compound having a structure in which a part of thehydrogen atoms or all hydrogen atoms included in the following silanecompounds are substituted with the fluorine atom(s). Concrete examplesof following silane compounds include dimethyl dimethoxy silane, diethyldiethoxy silane, 1-propenyl methyl dichloro silane, propyl dimethylchloro silane, propyl methyl dichloro silane, propyl trichloro silane,propyl triethoxy silane, propyl trimethoxy silane, styryl ethyltrimethoxy silane, tetradecyl trichloro silane, 3-thiocyanate propyltriethoxy silane, p-tolyl dimethyl chloro silane, p-tolyl methyldichloro silane, p-tolyl trichloro silane, p-tolyl trimethoxy silane,p-tolyl triethoxy silane, di-n-propyl di-n-propoxy silane, diisopropyldiisopropoxy silane, di-n-butyl di-n-butyloxy silane, di-sec-butyldi-sec-butyloxy silane, di-t-butyl di-t-butyloxy silane, octadecyltrichloro silane, octadecyl methyl diethoxy silane, octadecyl triethoxysilane, octadecyl trimethoxy silane, octadecyl dimethyl chloro silane,octadecyl methyl dichloro silane, octadecyl methoxy dichloro silane,7-octenyl dimethyl chloro silane, 7-octenyl trichloro silane, 7-octenyltrimethoxy silane, octyl methyl dichloro silane, octyl dimethyl chlorosilane, octyl trichloro silane, 10-undecenyl dimethyl chloro silane,undecyl trichloro silane, vinyl dimethyl chloro silane, methyl dodecyldimethoxy silane, methyl dodecyl diethoxy silane, methyl octadecyldimethoxy silane, methyl octadecyl diethoxy silane, n-octyl methyldimethoxy silane, n-octyl methyl diethoxy silane, triacontyl dimethylchloro silane, triacontyl trichloro silane, methyl trimethoxy silane,methyl triethoxy silane, methyl tri-n-propoxy silane, methyltriisopropoxy silane, methyl tri-n-butyloxy silane, methyltri-sec-butyloxy silane, methyl tri-t-butyloxy silane, ethyl trimethoxysilane, ethyl triethoxy silane, ethyl tri-n-propoxy silane, ethyltri-isopropoxy silane, ethyl-n-butyloxy silane, ethyl tri-sec-butyloxysilane, ethyl tri-t-butyloxy silane, n-propyl trimethoxy silane,isobutyl trimethoxy silane, n-hexyl trimethoxy silane, hexadecyltrimethoxy silane, n-octyl trimethoxy silane, n-dodecyl triethoxysilane, n-octadecyl trimethoxy silane, n-propyl triethoxy silane,isobutyl triethoxy silane, n-hexyl triethoxy silane, hexadecyl triethoxysilane, n-octyl triethoxy silane, n-dodecyl trimethoxy silane,n-octadecyl triethoxy silane, 2-[2-(trichloro silyl)ethyl]pyridine,4-[2-(trichloro silyl)ethyl]pyridine, diphenyl dimethoxy silane,diphenyl diethoxy silane, 1,3-(trichloro silyl methyl) heptacosane,dibenzyl dimethoxy silane, dibenzyl diethoxy silane, phenyl trimethoxysilane, phenyl trimethyl dimethoxy silane, phenyl dimethyl methoxysilane, phenyl dimethoxy silane, phenyl diethoxy silane, phenyl methyldiethoxy silane, phenyl dimethyl ethoxy silane, benzyl triethoxy silane,benzyl trimethoxy silane, benzyl methyl dimethoxy silane, benzyldimethyl methoxy silane, benzyl dimethoxy silane, benzyl diethoxysilane, benzyl methyl diethoxy silane, benzyl dimethyl ethoxy silane,benzyl triethoxy silane, dibenzyl dimethoxy silane, dibenzyl diethoxysilane, 3-acetoxy propyl trimethoxy silane, 3-acryloxy propyl trimethoxysilane, allyl trimethoxy silane, allyl triethoxy silane, 4-amino butyltriethoxy silane, (amino ethyl amino methyl) phenethyl trimethoxysilane, N-(2-amino ethyl)-3-amino propyl methyl dimethoxy silane,N-(2-amino ethyl)-3-amino propyl trimethoxy silane, 6-(amino hexyl aminopropyl)trimethoxy silane, p-amino phenyl trimethoxy silane, p-aminophenyl ethoxy silane, m-amino phenyl trimethoxy silane, m-amino phenylethoxy silane, 3-amino propyl trimethoxy silane, 3-amino propyltriethoxy silane, ω-amino undecyl trimethoxy silane, amyl triethoxysilane, benzooxasilepin dimethyl ester, 5-(bicycloheptenyl)triethoxysilane, bis(2-hydroxy ethyl)-3-amino propyl triethoxy silane, 8-bromooctyl trimethoxy silane, bromo phenyl trimethoxy silane, 3-bromo propyltrimethoxy silane, n-butyl trimethoxy silane, 2-chloro methyl triethoxysilane, chloro methyl methyl diethoxy silane, chloro methyl methyldiisopropoxy silane, p-(chloro methyl) phenyl trimethoxy silane, chloromethyl triethoxy silane, chloro phenyl triethoxy silane, 3-chloro propylmethyl dimethoxy silane, 3-chloro propyl triethoxy silane, 3-chloropropyl trimethoxy silane, 2-(4-chloro sulfonyl phenyl)ethyl trimethoxysilane, 2-cyano ethyl triethoxy silane, 2-cyano ethyl trimethoxy silane,cyano methyl phenethyl triethoxy silane, 3-cyano propyl triethoxysilane, 2-(3-cyclohexenyl)ethyl trimethoxy silane,2-(3-cyclohexenyl)ethyl triethoxy silane, 3-cyclohexenyl trichlorosilane, 2-(3-cyclohexenyl)ethyl trichloro silane,2-(3-cyclohexenyl)ethyl dimethyl chloro silane, 2-(3-cyclohexenyl)ethylmethyl dichloro silane, cyclohexyl dimethyl chloro silane, cyclohexylethyl dimethoxy silane, cyclohexyl methyl dichloro silane, cyclohexylmethyl dimethoxy silane, (cyclohexyl methyl)trichloro silane, cyclohexyltrichloro silane, cyclohexyl trimethoxy silane, cyclooctyl trichlorosilane, (4-cyclooctenyl)trichloro silane, cyclopentyl trichloro silane,cyclopentyl trimethoxy silane, 1,1-diethoxy-1-silacyclopenta-3-en,3-(2,4-dinitro phenyl amino) propyl triethoxy silane, (dimethyl chlorosilyl) methyl-7,7-dimethyl norpinane, (cyclohexyl amino methyl) methyldiethoxy silane, (3-cyclopentadienyl propyl)triethoxy silane,N,N-diethyl-3-amino propyl)trimethoxy silane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxy silane, 2-(3,4-epoxy cyclohexyl)ethyltriethoxy silane, (furfuryl oxy methyl)triethoxy silane,2-hydroxy-4-(3-triethoxy propoxy)diphenyl ketone, 3-(p-methoxy phenyl)propyl methyl dichloro silane, 3-(p-methoxy phenyl) propyl trichlorosilane, p-(methyl phenethyl) methyl dichloro silane, p-(methylphenethyl)trichloro silane, p-(methyl phenethyl)dimethyl chloro silane,3-morpholino propyl trimethoxy silane, (3-glycidoxy propyl) methyldiethoxy silane, 3-glycidoxy propyl trimethoxy silane,1,2,3,4,7,7-hexachloro-6-methyl diethoxy silyl-2-norbornene,1,2,3,4,7,7-hexachloro-6-triethoxy silyl-2-norbornene, 3-iodo propyltrimethoxy silane, 3-isocyanate propyl triethoxy silane, (mercaptomethyl) methyl diethoxy silane, 3-mercapto propyl methyl dimethoxysilane, 3-mercapto propyl dimethoxy silane, 3-mercapto propyl triethoxysilane, 3-methacryloxy propyl methyl diethoxy silane, 3-methacryloxypropyl trimethoxy silane, methyl {2-(3-trimethoxy silyl propyl amino)ethyl amino}-3-propionate, 7-octenyl trimethoxy silane,R—N-α-phenethyl-N′-triethoxy silyl propyl urea,S—N-α-phenethyl-N′-triethoxy silyl propyl urea, phenethyl trimethoxysilane, phenethyl methyl dimethoxy silane, phenethyl dimethyl methoxysilane, phenethyl dimethoxy silane, phenethyl diethoxy silane, phenethylmethyl diethoxy silane, phenethyl dimethyl ethoxy silane, phenethyltriethoxy silane, (3-phenyl propyl)dimethyl chloro silane, (3-phenylpropyl) methyl dichloro silane, N-phenyl amino propyl trimethoxy silane,N-(triethoxy silyl propyl) dansyl amide, N-(3-triethoxy silylpropyl)-4,5-dihydro imidazol, 2-(triethoxy silyl ethyl)-5-(chloroacetoxy)bicyclo heptane, (S)—N-triethoxy silyl propyl-O-menthocarbamate,3-(triethoxy silyl propyl)-p-nitro benzamide, 3-(triethoxy silyl) propylsuccinic anhydrate, N-[5-(trimethoxysilyl)-2-aza-1-oxo-pentyl]caprolactam, 2-(trimethoxy silyl ethyl)pyridine, N-(trimethoxy silyl ethyl)benzyl-N,N,N-trimethyl ammoniumchloride, phenyl vinyl diethoxy silane, 3-thiocyanate propyl triethoxysilane, N-{3-(triethoxy silyl) propyl}phthalamic acid, 1-trimethoxysilyl-2-(chloro methyl) phenyl ethane, 2-(trimethoxy silyl)ethyl phenylsulfonyl azide, β-trimethoxy silyl ethyl-2-pyridine, trimethoxy silylpropyl diethylene triamine, N-(3-trimethoxy silyl propyl) pyrrole,N-trimethoxy silyl propyl-N,N,N-tributyl ammonium bromide, N-trimethoxysilyl propyl-N,N,N-tributyl ammonium chloride, N-trimethoxy silylpropyl-N,N,N-trimethyl ammonium chloride, vinyl methyl diethoxy silane,vinyl triethoxy silane, vinyl trimethoxy silane, vinyl methyl dimethoxysilane, vinyl dimethyl methoxy silane, vinyl dimethyl ethoxy silane,vinyl methyl dichloro silane, vinyl phenyl dichloro silane, vinyl phenyldiethoxy silane, vinyl phenyl dimethyl silane, vinyl phenyl methylchloro silane, vinyl triphenoxy silane, vinyl tris-t-butoxy silane,adamanthyl ethyl trichloro silane, allyl phenyl trichloro silane, (aminoethyl amino methyl) phenethyl trimethoxy silane, 3-amino phenoxydimethyl vinyl silane, phenyl trichloro silane, phenyl dimethyl chlorosilane, phenyl methyl dichloro silane, benzyl trichloro silane, benzyldimethyl chloro silane, benzyl methyl dichloro silane, phenethyldiisopropyl chloro silane, phenethyl trichloro silane, phenethyldimethyl chloro silane, phenethyl methyl dichloro silane, 5-(bicycloheptenyl)trichloro silane, 5-(bicycloheptenyl)triethoxy silane,2-(bicycloheptyl)dimethyl chloro silane, 2-(bicycloheptyl)trichlorosilane, 1,4-bis(trimethoxy silyl ethyl)benzene, bromo phenyl trichlorosilane, 3-phenoxy propyl dimethyl chloro silane, 3-phenoxy propyltrichloro silane, t-butyl phenyl chloro silane, t-butyl phenyl methoxysilane, t-butyl phenyl dichloro silane, p-(t-butyl) phenethyl dimethylchloro silane, p-(t-butyl) phenethyl trichloro silane, 1,3-(chlorodimethyl silyl methyl) heptacosane, ((chloro methyl) phenylethyl)dimethyl chloro silane, ((chloro methyl) phenyl ethyl) methyldichloro silane, ((chloro methyl) phenyl ethyl)trichloro silane,((chloro methyl) phenyl ethyl)trimethoxy silane, chloro phenyl trichlorosilane, 2-cyano ethyl trichloro silane, 2-cyano ethyl methyl dichlorosilane, 3-cyano propyl methyl diethoxy silane, 3-cyano propyl methyldichloro silane, 3-cyano propyl methyl dichloro silane, 3-cyano propyldimethyl ethoxy silane, 3-cyano propyl methyl dichloro silane, 3-cyanopropyl trichloro silane, and the like.

Further, it is preferred that the fluorine type silane compound (surfacetreatment agent) has a perfluoro alkyl structure (C_(n)F_(2n+1)). Thismakes it possible to further improve the storage stability of theultraviolet ray curable ink composition especially, and to make thegloss and the wear resistance of the printed portion of the printedobject produced by using the ultraviolet ray curable ink compositionmore excellent.

Examples of the fluorine type silane compound having such a perfluoroalkyl structure (C_(n)F_(2n+1)) include a compound represented by thefollowing formula (3).

C_(n)F_(2n+1)(CH₂)_(m)SiX¹ _(a)R² _((3−a))  (3)

In the above formula (3), “X¹” is a hydrolysable group, an ether group,a chloro group or a hydroxyl group, “R²” is an alkyl group having carbonnumbers in the range of 1 or more but 4 or less, “n” is an integralnumber in the range of 1 or more but 14 or less, “m” is an integralnumber in the range of 2 or more but 6 or less, and “a” is an integralnumber in the range of 1 or more but 3 or less.

Concrete examples of the compound having such a structure includeCF₃—CH₂CH₂—Si(OCH₃)₃, CF₃(CF₂)₃—CH₂CH₂—Si(OCH₃)₃,CF₃(CF₂)₅—CH₂CH₂—Si(OCH₃)₃, CF₃(CF₂)₅—CH₂CH₂—Si (OC₂H₅)₃,CF₃(CF₂)₇—CH₂CH₂—Si(OCH₃)₃, CF₃(CF₂)₁₁—CH₂CH₂—Si(OC₂H₅)₃, CF₃(CF₂)₃—CH₂CH₂—Si(CH₃)(OCH₃)₂, CF₃(CF₂)₇—CH₂CH₂—Si(CH₃)(OCH₃)₂,CF₃(CF₂)₈—CH₂CH₂—Si(CH₃)(OC₂H₅)₂, CF₃(CF₂)₈—CH₂CH₂—Si(C₂H₅)(OC₂H₅)₂, andthe like.

Further, as the fluorine type silane compound, a compound having aperfluoro alkyl ether structure (C_(n)F_(2n+1)O) instead of the abovementioned perfluoro alkyl structure (C_(n)F_(2n+1)) also can be used.

Examples of the fluorine type silane compound having such a perfluoroalkyl ether structure (C_(n)F_(2n+1)O) include a compound represented bythe following formula (4).

C_(p)F_(2p+1)O(C_(p)F_(2p)O)_(r)(CH₂)_(m)SiX¹ _(a)R² _((3−a))  (4)

In the above formula (4), “X¹” is a hydrolysable group, an ether group,a chloro group or a hydroxyl group, “R²” is an alkyl group having carbonnumbers in the range of 1 or more but 4 or less, “p” is an integralnumber in the range of 1 or more but 4 or less, “r” is an integralnumber in the range of 1 or more but 10 or less, “m” is an integralnumber in the range of 2 or more but 6 or less, and “a” is an integralnumber in the range of 1 or more but 3 or less.

Concrete examples of the compound having such a structure includeCF₃O(CF₂O)₆—CH₂CH₂—Si(OC₂H₅)₃, CF₃O(C₃F₆O)₄—CH₂CH₂—Si(OCH₃)₃,CF₃O(C₃F₆O)₂(CF₂O)₃—CH₂CH₂—Si(OCH₃)₃, CF₃O(C₃F₆O)₈—CH₂CH₂—Si(OCH₃)₃,CF₃O(C₄F₉O)₅—CH₂CH₂—Si(OCH₃)₃, CF₃O(C₄F₉O)₅—CH₂CH₂—Si(CH₃)(OC₂H5)₂,CF₃O(C₃F₆O)₄—CH₂CH₂—Si(C₂H₅)(OCH₃)₂, and the like.

Next, description will be made on a fluorine type phosphoric acid esterin the surface treatment agent in detail.

As the fluorine type phosphoric acid ester, a phosphoric acid esterhaving at least one fluorine atom in a molecule thereof can be used.

In particular, it is preferred that the ultraviolet ray curable inkcomposition of the invention includes the metal powder constituted fromthe metal particles which are subjected to the surface treatment withthe fluorine type phosphoric acid ester having a chemical structurerepresented by the following formula (2).

POR_(n)(OH)_(3−n)  (2)

where in the above formula (2), “R” is CF₃(CF₂)_(m)—,CF₃(CF₂)_(m)(CH₂)_(l)—, CF₃(CF₂)_(m)(CH₂O)_(l)—,CF₃(CF₂)_(m)(CH₂CH₂O)_(l)—, CF₃(CF₂)_(m)O— or CF₃(CF₂)_(m)(CH₂)_(l)O—,“n” is an integral number in the range of 1 or more but 3 or less, “m”is an integral number in the range of 5 or more but 17 or less, and “l”is an integral number in the range of 1 or more but 12 or less.

This makes it possible to improve the storage stability of theultraviolet ray curable ink composition especially, and the gloss andthe wear resistance of the printed portion of the printed objectproduced by using the ultraviolet ray curable ink composition.

In the above formula (2), “m” is preferably the integral number in therange of 5 or more but 17 or less, and more preferably the integralnumber in the range of 7 or more but 12 or less. This makes it possibleto more remarkably exhibit the above mentioned effects.

Further, in the above formula (2), “l” is preferably the integral numberin the range of 1 or more but 12 or less, and more preferably theintegral number in the range of 1 or more but 10 or less. This makes itpossible to more remarkably exhibit the above mentioned effects.

Further, it is preferred that the ultraviolet ray curable inkcomposition of the invention includes the metal powder constituted fromthe metal particles which are subjected to the surface treatment withthe fluorine type phosphoric acid ester represented byCF₃(CF₂)₅(CH₂)₂O(P)(OH)₂ and/or CF₃(CF₂)₅(CH₂)₂O(P)(OH)(OCH₂CH₃).

This ensures that the metal particles of the metal powder are subjectedto the surface treatment reliably and sufficiently. As a result, it ispossible to improve the chemical stability and the dispersion stabilityof the metal particles of the metal powder in the ultraviolet raycurable ink composition and make the storage stability and the ejectionstability for a long period of time of the ultraviolet ray curable inkcomposition excellent. Further, in the printed object produced by usingthe ultraviolet ray curable ink composition, it is possible to reliablyarrange the metal particles of the metal powder at the vicinity of theouter surface of the printed portion, thereby to efficiently exhibit thecharacteristics such as the gloss which are inherently possessed by themetal material of the metal particles constituting the metal powder.Further, even if a polymerizable compound having low surface tension isused as a constituent material of the ultraviolet ray curable inkcomposition, it is possible to reliably arrange the metal particles ofthe metal powder at the vicinity of the outer surface of the printedportion in the printed object produced by using the ultraviolet raycurable ink composition. Consequently, it is possible to efficientlyexhibit the characteristics such as the gloss which are inherentlypossessed by the metal material of the metal particles constituting themetal powder.

Further, it is preferred that the fluorine type phosphoric acid ester(surface treatment agent) has a perfluoro alkyl structure(C_(n)F_(2n+1)). This makes it possible to improve the storage stabilityof the ultraviolet ray curable ink composition especially, and the glossand the wear resistance of the printed portion of the printed objectproduced by using the ultraviolet ray curable ink composition.

The base particles may be directly subjected to the surface treatmentwith the surface treatment agent (the fluorine type silane compound,fluorine type phosphoric acid ester) as described above, but may bepreferably subjected to a treatment with an acid or a base, and then thesubjected base particles may be preferably subjected the surfacetreatment with the above surface treatment agent (fluorine type silanecompound and fluorine type phosphoric acid ester). This makes itpossible to reliably modify the surfaces of the base particles with theabove surface treatment agent (fluorine type silane compound and/orfluorine type phosphoric acid ester) due to a chemical bonding thereof,thereby exhibiting the above mentioned effects of the invention in amore effective manner. Examples of the acid include a proton acid suchas hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid,acetic acid, carbonic acid, formic acid, benzoic acid, chlorous acid,hypochlorous acid, sulfurous acid, hyposulfurous acid, nitrous acid,hyponitrous acid, phosphorous acid, hypophosphorous acid and the like.Among them, it is preferably the hydrochloric acid, the phosphoric acidand the acetic acid. On the other hand, examples of the base includesodium hydroxide, potassium hydroxide, calcium hydroxide and the like.Among them, it is preferably the sodium hydroxide and the potassiumhydroxide.

Each of the metal particles of the metal powder may be of any shape suchas a spherical shape, a fusiform shape or a needle shape, but ispreferably of a scaly shape. This makes it possible to arrange the metalparticle of the metal powder on a recording medium, on which theultraviolet ray curable ink composition is to be applied, so that amajor surface of the metal particle of the metal powder are orientedalong a surface shape of the recording medium. Therefore, it is alsopossible to more effectively exhibit the gloss and the like providedinherently by the metal material constituting the metal particles of themetal powder in the printed object to be produced, to thereby make thegloss and the high-grade sense of the pattern (printed portion) to beformed especially excellent. Furthermore, in the case where the metalparticles are not subjected to the surface treatment with the fluorinetype silane compound and/or the fluorine type phosphoric acid ester asdescribed above, if each of the metal particles of the metal powder isof the scaly shape, the storage stability and the ejection stability ofthe ultraviolet ray curable ink composition are apt to be furtherremarkably lowered. In contrast, in the invention, even if each of themetal particles of the metal powder is of the scaly shape, it ispossible to prevent such a problem from occurring reliably. In otherwords, in the case where each of the metal particles of the metal powderis of the scaly shape, the effects of the invention can be moreremarkably exhibited.

In the invention, the scaly shape means a shape in which an area of theparticle observed from a predetermined direction (that is, an area ofeach particle at a planar view thereof) is larger than an area of theparticle observed from a direction orthogonal to the above observationdirection, such as a plate shape or a curved plate shape. In particular,in the case where an area of the particle observed from a directionwhere a project area thereof becomes maximum (that is, an area of eachparticle at a planar view thereof) is defined as S₁ (μm²) and an area ofthe particle observed from a direction where the area of the particleobserved from directions orthogonal to the above observation directionbecomes maximum is defined as S₀ (μm²), especially, a ratio of S₁ to S₀(S₁/S₀) is preferably 2 or more, more preferably 5 or more, and evenmore preferably or more. For example, as the value of this ratio, anaverage value of the values of the ratios obtained by observingarbitrary 10 particles can be used.

An average particle size (thickness) of the metal particles of the metalpowder is preferably in the range of 500 nm or more but 3.0 μm or less,and more preferably in the range of 800 nm or more but 1.8 μm or less.This makes it possible to further improve the gloss and the high-gradesense of the printed object to be produced by using the ultraviolet raycurable ink composition. Further, this also makes it possible to makethe storage stability and the ejection stability of the ultraviolet raycurable ink composition more excellent.

An amount of the metal particles of the metal powder contained in theultraviolet ray curable ink composition is preferably in the range of0.5 mass % or more but 10.0 mass % or less, and more preferably in therange of 1.0 mass % or more but 5.0 mass % or less. In this regard, theultraviolet ray curable ink composition may contain two or more kinds ofpowder as the metal powder. In this case, a total amount of them ispreferably any value which falls within the above ranges.

Polymerizable Compound

A polymerizable compound is a component capable of being cured due topolymerization thereof by being irradiated with an ultraviolet ray. Bycontaining such a component, it is possible to improve the wearresistance, the water resistance, the solvent resistance and the like ofthe printed object to be produced by using the ultraviolet ray curableink composition.

In particular, it is preferred that a monomer having an alicyclicstructure is contained as the polymerizable compound in the ultravioletray curable ink composition of the invention. By containing the monomerhaving the alicyclic structure together with the metal powder of whichmetal particles are subjected to the surface treatment with the fluorinetype silane compound and/or the fluorine type phosphoric acid ester, itis possible to improve the storage stability of the ultraviolet raycurable ink composition especially, and the gloss and the wearresistance of the printed portion of the printed object produced byusing the ultraviolet ray curable ink composition.

The reason why such excellent effects are obtained is as follows. Byincluding the metal powder of which metal particles are subjected to thesurface treatment with the fluorine type silane compound and/or thefluorine type phosphoric acid ester, in the ultraviolet ray curable inkcomposition applied onto the recording medium, it is possible toreliably arrange the metal particles of the metal powder at the vicinityof the outer surface of the recording medium, so that the metalparticles of the metal powder arrange at the vicinity of an outersurface of a printed portion in the finally obtained printed objectreliably. Therefore, it is possible to obtain excellent gloss of theprinted object (printed portion). Further, by containing the monomerhaving the alicyclic structure in the ultraviolet ray curable inkcomposition, it is possible to reliably improve the dispersion stabilityof the metal powder of which metal particles are subjected to thesurface treatment with the fluorine type silane compound and/or thefluorine type phosphoric acid ester. As a result, it is possible toreliably prevent the metal particles of the metal powder fromaggregating and settling in the ultraviolet ray curable ink compositionfor a long period of time. By acting synergistically on the effects, itis possible to improve the storage stability of the ultraviolet raycurable ink composition especially, and the gloss and wear resistance ofthe printed portion of the printed object produced by using theultraviolet ray curable ink composition.

The excellent effects as described above are obtained by containing themonomer having the alicyclic structure together with the metal powderconstituted of the metal particles which are subjected to the surfacetreatment with the fluorine type silane compound and/or the fluorinetype phosphoric acid ester in the ultraviolet ray curable inkcomposition. In the case where one of the metal powder and the monomeris not contained in the ultraviolet ray curable ink composition, theexcellent effects as described above are not obtained.

In the case where the metal powder of which metal particles aresubjected to the surface treatment with the fluorine type silanecompound and/or the fluorine type phosphoric acid ester is contained,but the monomer having the alicyclic structure is not contained in theultraviolet ray curable ink composition, it is possible to reliablyarrange the metal particles of the metal powder at the vicinity of outersurfaces of droplets of the ultraviolet ray curable ink composition.However, the dispersibility of the metal powder in the ultraviolet raycurable ink composition is lowered conspicuously, thereby making thedroplet ejection by the ink jet method conspicuously unstable. In thiscase, the ejection stability of the droplets of the ultraviolet raycurable ink composition is lowered with time conspicuously, so that itbecomes difficult or impossible to perform the droplet ejection inrelatively a short period of time.

On the other hand, in the case where the monomer having the alicyclicstructure is contained, but the metal powder of which metal particlesare subjected to the surface treatment with the fluorine type silanecompound and/or the fluorine type phosphoric acid ester is not containedin the ultraviolet ray curable ink composition, the dispersibility ofthe metal powder are not lowered conspicuously. However, it becomesdifficult to reliably arrange the metal particles of the metal powder atthe vicinity of the outer surface of the recording medium in theultraviolet ray curable ink composition applied onto the recordingmedium, so that it is not possible to obtain sufficiently the excellentgloss of the finally obtained printed object (printed portion) reliably.

Examples of the monomer having the alicyclic structure includetris(2-(metha)acryloyloxy ethyl) isocyanurate, dicyclopentenyloxyethyl(metha)acrylate, adamantyl(metha)acrylate,γ-butyrolactone(metha)acrylate, N-vinyl caprolactam, N-vinylpyrrolidone, pentamethyl piperidyl(metha)acrylate, tetramethylpiperidyl(metha)acrylate, 2-methyl-2-adamantyl(metha)acrylate,2-ethyl-2-adamantyl(metha)acrylate, mevalonic acidlactone(metha)acrylate, dimethylol tricyclodecane di(metha)acrylate,dimethylol dicyclopentane di(metha)acrylate,dicyclopentenyl(metha)acrylate, dicyclopentanyl(metha)acrylate,isobornyl(metha)acrylate, cyclohexyl(metha)acrylate,(metha)acryloylmorpholine, tetrahydrofurfuryl(metha)acrylate, phenyl glycidylether(metha)acrylate, EO modified water addition bisphenol Adi(metha)acrylate, di(metha)acrylated isocyanurate, tri(metha)acrylatedisocyanurate, and the like. It is preferred that the monomer includesone or more selected from the group consisting of tris(2-acryloyloxyethyl) isocyanurate, dicyclopentenyl oxyethyl acrylate, adamantylacrylate, γ-butyrolactone acrylate, N-vinyl caprolactam, N-vinylpyrrolidone, pentamethyl piperidyl acrylate, tetramethyl piperidylacrylate, 2-methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl acrylate,mevalonic acid lactone acrylate, dimethylol tricyclodecane diacrylate,dimethylol dicyclopentane diacrylate, dicyclopentenyl acrylate,dicyclopentanyl acrylate, isobornyl acrylate, cyclohexyl acrylate,acryloyl morpholine, and tetrahydrofurfuryl acrylate. This makes itpossible to further improve the gloss and the high-grade sense of theprinted object to be produced by using the ultraviolet ray curable inkcomposition. Furthermore, it is possible to further improve the storagestability and the ejection stability of the ultraviolet ray curable inkcomposition.

Among them, in the case where the monomer includes one or more selectedfrom the group consisting of acryloyl morpholine, tetrahydrofurfurylacrylate, γ-butyrolactone acrylate, N-vinyl caprolactam, and N-vinylpyrrolidone, it is possible to further improve the dispersion stabilityof the metal particles of the metal powder in the ultraviolet raycurable ink composition. In addition to that, in the printed objectproduced by using the ultraviolet ray curable ink composition, it ispossible to reliably arrange the metal particles of the metal powder atthe vicinity of the outer surface of the printed portion, so that it ispossible to further improve the gloss of the obtained printed object.

From a point of view of further improving a curing rate of theultraviolet ray curable ink composition at the time of irradiating withthe ultraviolet ray and the productivity of the printed object, it ispreferred that the monomer includes one or more selected from the groupconsisting of tris(2-acryloyloxy ethyl) isocyanurate, dicyclopentenyloxyethyl acrylate, γ-butyrolactone acrylate, N-vinyl pyrrolidone,dimethylol tricyclodecane diacrylate, dimethylol dicyclopentanediacrylate, dicyclopentenyl acrylate, dicyclopentanyl acrylate, acryloylmorpholine, and tetrahydrofurfuryl acrylate. Moreover, the monomerincludes more preferably acryloyl morpholine and/or γ-butyrolactoneacrylate, and even more preferably γ-butyrolactone acrylate.

Further, in the case where the monomer includes cyclohexyl acrylateand/or tetrahydrofurfuryl acrylate, it is possible to further improvethe flexibility of the printed portion formed by curing the ultravioletray curable ink composition.

From a point of view of further improving the wear resistance of theprinted portion formed by curing the ultraviolet ray curable inkcomposition, it is preferred that the monomer includes one or moreselected from the group consisting of tris(2-acryloyloxy ethyl)isocyanurate, dicyclopentenyl oxyethyl acrylate, adamantyl acrylate,γ-butyrolactone acrylate, N-vinyl caprolactam, N-vinyl pyrrolidone,dimethylol tricyclodecane diacrylate, dimethylol dicyclopentanediacrylate, dicyclopentenyl acrylate, dicyclopentanyl acrylate,isobornyl acrylate, and acryloyl morpholine. Moreover, the monomerincludes more preferably γ-butyrolactone acrylate and/or N-vinylcaprolactam.

Further, in the case where the monomer includes one or more selectedfrom the group consisting of γ-butyrolactone acrylate, N-vinylcaprolactam, N-vinyl pyrrolidone, isobornyl acrylate, andtetrahydrofurfuryl acrylate, it is possible to lower a shrinkage ratioof the ultraviolet ray curable ink composition at the time of curing.Consequently, it is possible to efficiently prevent the gloss of theprinted portion from lowering due to occurrence of involuntary wrinkleson the printed portion formed by curing the ultraviolet ray curable inkcomposition.

An amount of the monomer having the alicyclic structure contained in theultraviolet ray curable ink composition is preferably in the range of 40mass % or more but 90 mass % or less, more preferably in the range of 50mass % or more but 88 mass % or less, and even more preferably in therange of 55 mass % or more but 85 mass % or less. This makes it possibleto improve the dispersion stability of metal particles of metal powderespecially, and therefore obtain the ejection stability of theultraviolet ray curable ink composition for the long period of time. Inparticular, even if the ultraviolet ray curable ink composition does notcontain a dispersant, the excellent effects as described above areobtained. In contrast, if the amount of the monomer having the alicyclicstructure contained in the ultraviolet ray curable ink composition issmaller than the lower limit value noted above, there is a possibilitythat the dispersion stability of the metal powder of which metalparticles are subjected to the surface treatment with the fluorine typesilane compound and/or the fluorine type phosphoric acid ester islowered, so that the stability of the droplet ejection by the ink jetmethod is lowered. Further, in this case, there is a possibility thatthe stability over time of the droplet ejection of the ultraviolet raycurable ink composition is also lowered. Further, if the amount of themonomer having the alicyclic structure contained in the ultraviolet raycurable ink composition exceeds the upper limit value noted above, thereare the following possibilities. An amount of the metal powder existingin the ultraviolet ray curable ink composition applied onto therecording medium is increased by excess improvement of the dispersionstability of the metal powder. Therefore, it is difficult to reliablyarrange the metal particles of the metal powder at the vicinity of theouter surface of the ultraviolet ray curable ink composition appliedonto the recording medium. Thus, it becomes difficult to obtain enoughexcellent gloss of the finally obtained printed object (printedportion). In this regard, the ultraviolet ray curable ink compositionmay contain two or more kinds of compounds as the monomer having thealicyclic structure. In this case, a total amount of them is preferablyany value which falls within the above ranges.

In the monomer having the alicyclic structure, the number of atomsconstituting the cyclic structure formed by the covalent bonds ispreferably 5 or more, and more preferably 6 or more. This makes itpossible to obtain the ultraviolet ray curable ink composition havingexcellent storage stability.

It is preferred that the ultraviolet ray curable ink compositioncontains a monofunctional monomer including a hetero atom in analiciclic structure (monofunctional monomer including a hetero ringhaving no aromatic property) as the monomer having the alicyclicstructure. This makes it possible to provide excellent dispersionstability of metal particles of metal powder, and therefore obtain theejection stability of the ultraviolet ray curable ink composition forthe long period of time. In particular, even if the ultraviolet raycurable ink composition does not contain the dispersant, the excellenteffects as described above are obtained. The reason why the monomerhaving the alicyclic structure makes the dispersion stability of themetal powder improve is unclear. However, the inventors consider thereason why the hetero atom of the alicyclic structure has an appropriateaffinity with respect to the surfaces of the metal particles, which aremodified by a fluorine atom, of the metal powder. Examples of such amonofunctional monomer include tris(2-(metha)acryloyloxy ethyl)isocyanurate, γ-butyrolactone(metha)acrylate, N-vinyl caprolactam,N-vinyl pyrrolidone, pentamethyl piperidyl(metha)acrylate, tetramethylpiperidyl(metha)acrylate, mevalonic acidlactone(metha)acrylate,(metha)acryloyl morpholine,tetrahydrofurfuryl(metha)acrylate, and the like.

An amount of the monofunctional monomer contained in the ultraviolet raycurable ink composition (monofunctional monomer including the heteroatom in the alicyclic structure) is preferably in the range of 10 mass %or more but 80 mass % or less, and more preferably in the range of 15mass % or more but 75 mass % or less. This makes it possible to suppresscure shrinkage of the ultraviolet ray curable ink composition, therebyobtaining the ultraviolet ray curable ink composition in which the metalparticles are scattered in a small amount thereof. Consequently, it ispossible to reliably use the ultraviolet ray curable ink composition forproducing the printed object provided with the pattern (printed portion)having excellent gloss. In this regard, the ultraviolet ray curable inkcomposition may contain two or more kinds of compounds as themonofunctional monomer including the hetero atom in the alicyclicstructure. In this case, a total amount of them is preferably any valuewhich falls within the above ranges.

In the invention, the polymerizable compound constituting theultraviolet ray curable ink composition may include the monomer havingthe alicyclic structure as described above. In addition to that, thepolymerizable compound may include a monomer having no alicyclicstructure.

Examples of such a monomer (monomer having no alicyclic structure)include one or more selected from the group consisting of phenoxyethyl(metha)acrylate, 2-(2-vinyloxy ethoxy) ethyl(metha)acrylate,dipropylene glycol di(metha)acrylate, tripropylene glycoldi(metha)acrylate, 2-hydroxy-3-phenoxy propyl(metha)acrylate, 4-hydroxybutyl(metha)acrylate, laury(metha)acrylate, 2-methoxyethyl(metha)acrylate, isooctyl(metha)acrylate, stearyl(metha)acrylate,2-ethoxy ethyl(metha)acrylate, benzyl(metha)acrylate,1H,1H,5H-octafluoro pentyl(metha)acrylate, 2-hydroxyethyl(metha)acrylate, 2-hydroxy propyl(metha)acrylate,isobutyl(metha)acrylate, t-butyl(metha)acrylate, ethylcarbitol(metha)acrylate, 2,2,2-trifluoro ethyl(metha)acrylate,2,2,3,3-tetrafluoro propyl(metha)acrylate, methoxy triethyleneglycol(metha)acrylate, PO-modified nonyl phenol(metha)acrylate,EO-modified nonyl phenol(metha)acrylate, EO-modified 2-ethylhexyl(metha)acrylate, phenoxy diethylene glycol(metha)acrylate,EO-modified phenol(metha)acrylate, EO-modified cresol(metha)acrylate,methoxy polyethylene glycol(metha)acrylate, dipropyleneglycol(metha)acrylate, 2-n-butyl-2-ethyl-1,3-propanedioldi(metha)acrylate, tetraethylene glycol di(metha)acrylate,1,9-nonanediol di(metha)acrylate, 1,4-butanediol di(metha)acrylate,bisphenol A EO-modified di(metha)acrylate, 1,6-hexanedioldi(metha)acrylate, polyethylene glycol 200 di(metha)acrylate,polyethylene glycol 300 di(metha)acrylate, neopentyl glycol hydroxylpivalate di(metha)acrylate, 2-ethyl-2-butyl-propanedioldi(metha)acrylate, polyethylene glycol 400 di(metha)acrylate,polyethylene glycol 600 di(metha)acrylate, polypropylene glycoldi(metha)acrylate, bisphenol A EO-modified di(metha)acrylate,PO-modified bisphenol A di(metha)acrylate, trimethylol propanetri(metha)acrylate, pentaerythritol tri(metha)acrylate, trimethylolpropane EO-modified tri(metha)acrylate, glycerine PO-addedtri(metha)acrylate, tris(metha)acryloyl oxy ethyl phosphate,pentaerythritol tetra(metha)acrylate, PO-modified trimethylol propanetri(metha)acrylate, 2-(metha)acryloyloxy ethylphtalate,3-(metha)acryloyloxy propylacrylate, w-carboxy(metha)acryloyloxyethylphtalate, ditrimethylol propane tetra(metha)acrylate,dipentaerythritol penta/hexa(metha)acrylate, dipentaerythritolhexa(metha)acrylate, and the like. It is preferred that the monomerincludes one or more selected the group consisting of phenoxy ethylacrylate, 2-(2-vinyloxy ethoxy) ethyl acrylate, dipropylene glycoldiacrylate, tripropylene glycol diacrylate, 2-hydroxy-3-phenoxy propylacrylate, and 4-hydroxy butyl acrylate. The inclusion of such a monomerhaving no alicyclic structure makes it possible to improve the storagestability and the ejection stability of the ultraviolet ray curable inkcomposition especially. As are result, it is possible to obtainexcellent reactivity of the ultraviolet ray curable ink compositionafter the ejection by the ink jet method. Further, it is possible toimprove the productivity of the printed object especially. Consequently,it is possible for the pattern to be formed to exhibit excellent wearresistance.

Among them, in the case where the monomer include phenoxy ethylacrylate, in the printed object produced by using the ultraviolet raycurable ink composition, it is possible to reliably arrange the metalparticles of the metal powder at the vicinity of the outer surface ofthe printed portion, so that it is possible to obtain the excellentgloss of the printed portion in the obtained printed object reliably.

Further, in the case where the monomer includes 2-(2-vinyloxy ethoxy)ethyl acrylate, it is possible to improve a curing rate of theultraviolet ray curable ink composition when the ultraviolet ray isirradiated it and the productivity of the printed object.

Further, in the case where the monomer includes phenoxy ethyl acrylateand/or 2-hydroxy-3-phenoxy propyl acrylate, it is possible to improveflexibility of the printed portion formed by curing the ultraviolet raycurable ink composition.

From a point of view of further improving the wear resistance of theprinted portion of the printed object formed by curing the ultravioletray curable ink composition, it is preferred that the monomer includesone or more selected from the group consisting of 2-(2-vinyloxy ethoxy)ethyl acrylate, dipropylene glycol diacrylate, and tripropylene glycoldiacrylate. Moreover, the monomer includes more preferably 2-(2-vinyloxyethoxy) ethyl acrylate.

Further, in the case where the monomer includes phenoxy ethyl acrylate,it is possible to lower a shrinkage ratio of the ultraviolet ray curableink composition at the time of curing. Consequently, it is possible toefficiently prevent the gloss of the printed portion from lowering dueto occurrence of involuntary wrinkles on the printed portion of theprinted object formed by curing the ultraviolet ray curable inkcomposition.

An amount of a monomer other than the monomer having the alicyclicstructure contained in the ultraviolet ray curable ink composition ispreferably in the range of 5 mass % or more but 50 mass % or less, andmore preferably in the range of 10 mass % or more but 40 mass % or less.This ensures that it becomes easy to adjust the curing rate of theultraviolet ray curable ink composition, flexibility, the shrinkageratio of the ultraviolet ray curable ink composition at the time ofcuring, and the like. In this regard, the ultraviolet ray curable inkcomposition may contain two or more kinds of compounds as the monomerhaving no alicyclic structure. In this case, a total amount of them ispreferably any value which falls within the above ranges.

The monomer as described above, generally, is constituted in a liquidform by itself. Therefore, it is not necessary to use a dispersionmedium to be moved (evaporated) in the processes of producing theprinted object separately. In addition, it is not also necessary to gothrough a step of removing the dispersion medium in the processes ofproducing the printed object. Therefore, it is possible to improve theproductivity of the printed object especially. Further, it is notnecessary to use any solvent such as an organic solvent generally usedas a dispersion medium. Therefore, it is possible to prevent an issue ofa volatile organic compound (VOC) from generating. Furthermore,inclusion of the monomer as described above ensures to further improveadhesion of the printed portion of the printed object formed by usingthe ultraviolet ray curable ink composition with respect to variouskinds of recording mediums (base materials). That is, by containing themonomer as described above, the ultraviolet ray curable ink compositionexhibits excellent media responsibility.

The ultraviolet ray curable ink composition may contain an oligomer(including a dimer, a trimer and the like), a prepolymer and the likeother than the monomer as the polymerizable compound. As the oligomerand the prepolymer, for example, ones having the monomer as describedabove as a constituent component are used. It is preferred that theultraviolet ray curable ink composition contains a multifunctionaloligomer in particular. This makes it possible to especially improve thestorage stability of the ultraviolet ray curable ink composition and thewear resistance and the like of the pattern to be formed especially. Asthe oligomer, an urethane oligomer in which the repeating units areurethane units or an epoxy oligomer in which the repeating units areepoxy units can be preferably used.

An amount of the polymerizable compound contained in the ultraviolet raycurable ink composition is preferably in the range of 70 mass % or morebut 99 mass % or less, and more preferably in the range of 80 mass % ormore but 98 mass % or less. This makes it possible to especially improvethe storage stability, the ejection stability and the curing property ofthe ultraviolet ray curable ink composition especially, and the gloss,the wear resistance and the like of the printed object to be produced byusing the ultraviolet ray curable ink composition. In this regard, it isto be noted that the ultraviolet ray curable ink composition may containtwo or more kinds of compounds as the polymerizable compound. In thiscase, it is preferred that a total amount of these compounds is set to avalue falling within the above range.

Substance A

Furthermore, it is preferred that the ultraviolet ray curable inkcomposition of the invention includes a substance A having a partialstructure represented by the following formula (5).

where in the formula (5), “R¹” is an oxygen atom, a hydrogen atom, ahydrocarbon group or an alkoxyl group, and each of “R²”, “R³”, “R⁴” and“R⁵” is independently a hydrogen atom or a hydrocarbon group.

In the case where the ultraviolet ray curable ink composition containsthe substance A having such a chemical structure together with the metalparticles subjected to the surface treatment as described above and themonomer having the alicyclic structure, it is possible to make thestorage stability and the curing property of the ultraviolet ray curableink composition excellent. Further, in the printed object to be producedby using the ultraviolet ray curable ink composition, it is possible toexhibit the gloss and the high-grade sense provided inherently by themetal material constituting the metal particles of the metal powderefficiently. Consequently, it is also possible to make the gloss and thewear resistance of the printed portion superior, to thereby improve thedurability of the printed object.

In the above formula (5), “R¹” may be the oxygen atom, the hydrogenatom, the hydrocarbon group or the alkoxyl group (in which a chain typeor alicyclic type hydrocarbon group is bonded to an oxygen atom), but isespecially preferably the hydrogen atom, a methyl group or an octyl oxygroup. This makes it possible to especially improve the storagestability and the ejection stability of the ultraviolet ray curable inkcomposition, and the gloss and the wear resistance of the printedportion to be formed by using the ultraviolet ray curable inkcomposition.

Further, in the above formula (5), each of “R²” to “R⁵” may beindependently the hydrogen atom or the hydrocarbon group, but ispreferably an alkyl group having carbon atoms in the range of 1 or morebut 3 or less, and more preferably a methyl group. This makes itpossible to especially improve the storage stability and the ejectionstability of the ultraviolet ray curable ink composition, and the glossand the wear resistance of the printed portion to be formed by using theultraviolet ray curable ink composition.

An amount of the substance A contained in the ultraviolet ray curableink composition is preferably in the range of 0.1 mass % or more but 5.0mass % or less, and more preferably in the range of 0.5 mass % or morebut 3.0 mass % or less. This makes it possible to especially improve thestorage stability, the ejection stability and the curing property of theultraviolet ray curable ink composition, and the gloss, the wearresistance and the like of the printed object to be produced by usingthe ultraviolet ray curable ink composition. In this regard, it is to benoted that the ultraviolet ray curable ink composition may contain twoor more kinds of compounds as the substance A. In this case, it ispreferred that a total amount of these compounds is set to a valuefalling within the above range.

In the case where the amount of the substance A contained in theultraviolet ray curable ink composition is defined as X_(A) [mass %] andthe amount of the metal particles of the metal powder contained thereinis defined as X_(M) [mass %], X_(A) and X_(M) satisfy preferably arelationship of 0.01≦X_(A)/X_(M)≦0.8, and more preferably a relationshipof 0.05≦X_(A)/X_(M)≦0.4. By satisfying such a relationship, it ispossible to especially improve the storage stability and the ejectionstability of the ultraviolet ray curable ink composition, and to makethe gloss and the wear resistance of the printed portion to be formed byusing the ultraviolet ray curable ink composition especially excellent.

Dispersant

The ultraviolet ray curable ink composition of the invention may containa metal dispersant in a powder form (hereinafter, referred to as simply“dispersant”). This makes it possible to especially improve the storagestability of the ultraviolet ray curable ink composition.

In particular, the ultraviolet ray curable ink composition of theinvention may contain a compound having a polymer structure and basicproperty as the dispersant in the powder form (hereinafter, referred toas “basic polymer dispersant”). This ensures that the storage stabilityof the ultraviolet ray curable ink composition is excellent.

In this regard, it is to be noted that a specific molecular weight ofthe basic polymer dispersant is not limited particularly as long as thebasic polymer dispersant has the basic property and the polymerstructure.

The polymer structure constituting the basic polymer dispersant is notlimited particularly. Examples of such a polymer structure include anacrylic-based polymer structure (including a copolymer), amethacrylic-based polymer structure (including a copolymer), apolyurethane-based polymer structure, a hydroxyl group-containingcarboxylate ester structure, a polyether-based polymer structure, asilicone-based polymer structure and the like.

An amine number of the basic polymer dispersant is not limitedparticularly, but is preferably in the range of 3 mgKOH/g or more but 80mgKOH/g or less, and more preferably in the range of 10 mgKOH/g or morebut 70 mgKOH/g or less.

Examples of the basic polymer dispersant used in the invention includeDISPERBYK-116 (produced by BYK Japan KK), DISPERBYK-182 (produced by BYKJapan KK), DISPERBYK-183 (produced by BYK Japan KK), DISPERBYK-184(produced by BYK Japan KK), DISPERBYK-2155 (produced by BYK Japan KK),DISPERBYK-2164 (produced by BYK Japan KK), DISPERBYK-108 (produced byBYK Japan KK), DISPERBYK-112 (produced by BYK Japan KK), DISPERBYK-198(produced by BYK Japan KK), DISPERBYK-2150 (produced by BYK Japan KK),PAA-1112 (produced by Nitto Boseki Co., Ltd.), and the like.

In the case where the ultraviolet ray curable ink composition containsthe dispersant, an amount of the dispersant contained in the ultravioletray curable ink composition is preferably 5.0 mass % or less, and morepreferably in the range of 0.01 mass % or more but 2.0 mass % or less.This makes it possible to especially improve the storage stability, theejection stability and the curing property of the ultraviolet raycurable ink composition, and the gloss of the printed object to beproduced by using the ultraviolet ray curable ink composition. In thisregard, it is to be noted that the ultraviolet ray curable inkcomposition may contain two or more kinds of compounds as the basicpolymer dispersant. In this case, it is preferred that a total amount ofthese compounds is set to a value falling within the above range. If theamount of the dispersant contained in the ultraviolet ray curable inkcomposition is too large, the ratio of the metal particles of the metalpowder existing in the ultraviolet ray curable ink composition increasesin the ultraviolet ray curable ink composition applied onto therecording medium by the excess improvement of the dispersibility of themetal powder, so that it is difficult to reliably arrange the metalparticles of the metal powder at the vicinity of the outer surface ofthe applied ultraviolet ray curable ink composition. Consequently, thereis a possibility that it becomes difficult to improve the gloss of thefinally obtained printed object (printed portion) sufficiently.

Other Components

The ultraviolet ray curable ink composition of the invention may containcomponents other than the above mentioned components (that is, othercomponents). Examples of such other components include aphotopolymerization initiator, a slipping agent (leveling agent), apolymerization accelerator, a polymerization inhibitor, a penetrationaccelerator, a wetting agent (moisturizing agent), a coloring agent, afixing agent, an antifungal agent, an antiseptic agent, an antioxidant,a chelating agent, a thickening agent, a sensitizing agent (sensitizingdye) and the like.

The photopolymerization initiator is not limited to a specific type, aslong as it can generate active species such as radicals, cations and thelike by being irradiated with an ultraviolet ray, and thus can start apolymerization reaction of the polymerizable compound. As thephotopolymerization initiator, a photo radical polymerization initiatoror a photo cation polymerization initiator can be used, but the photoradical polymerization initiator can be preferably used. In the casewhere the photopolymerization initiator is used, it is preferred thatthe photopolymerization initiator has an absorption peak within anultraviolet region.

Examples of the photo radical polymerization initiator include aromaticketones, an acyl phosphine oxide compound, an aromatic onium saltcompound, an organic peroxide, a thiocompound (e.g., a thioxanthonecompound, a thiophenyl group containing compound), a hexaarylbiimidazole compound, a ketooxime ester compound, a borate compound, anazinium compound, a metallocene compound, an activated ester compound, acompound including a carbon-halogen bond, an alkyl amine compound andthe like.

From the viewpoint of solubility with respect to the polymerizablecompound and a curing property thereof, among them, at least oneselected from the group consisting of the acyl phosphine oxide compoundand the thioxanthone compound is preferable, and a combination of theacyl phosphine oxide compound and the thioxanthone compound is morepreferable.

Concrete examples of the photo radical polymerization initiator includeacetophenone, acetophenone benzyl ketal, 1-hydroxy cyclohexyl phenylketone, 2,2-dimethoxy-2-phenyl acetophenone, xanthone, fluorenone,benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole,3-methyl acetophenone, 4-chloro benzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diamino benzophenone, Michler's ketone, benzoinpropyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-on,2-hydroxy-2-methyl-1-phenylpropane-1-on, thioxanthone, diethylthioxanthone, 2-isopropyl thioxanthone, 2-chloro thioxanthone,2-methyl-1-[4-(methylthio) phenyl]-2-morpholino-propane-1-on,bis(2,4,6-trimethyl benzoyl)-phenyl phosphineoxide, 2,4,6-trimethylbenzoyl-diphenyl phosphineoxide, 2,4-diethyl thioxanthone,bis(2,6-dimethoxy benzoyl)-2,4,4-trimethyl pentyl phosphineoxide, andthe like. One of them can be used alone or two or more of them can beused in combination.

An amount of the photopolymerization initiator contained in theultraviolet ray curable ink composition is preferably in the range of0.5 mass % or more but 10 mass % or less. If the amount of thephotopolymerization initiator falls within the above range, a curingrate of the ultraviolet ray curable ink composition becomes sufficientlyhigh, and an insoluble matter of the photopolymerization initiator orcoloring resulting from the photopolymerization initiator is hardlygenerated.

In the case where the ultraviolet ray curable ink composition containsthe slipping agent, a surface of the printed object becomes smooth dueto a leveling effect thereof. This makes it possible to improve the wearresistance of the printed object.

The slipping agent is not limited to a specific kind. As the slippingagent, a silicone-based surfactant such as a polyester-modifiedsilicone, a polyether-modified silicone or a polyacrilate-modifiedsilicone, and a high molecular weight-based surfactant such aspolyacrylate and polyester can be used, and polyether-modifiedpolydimethyl siloxane, polyester-modified polydimethyl siloxane orpolyacrylate-modified dimethyl siloxane can be preferably used.

The ultraviolet ray curable ink composition of the invention may containthe polymerization inhibitor. However, even if the ultraviolet raycurable ink composition contains the polymerization inhibitor, an amountof the polymerization inhibitor contained in the ultraviolet ray curableink composition is preferably 0.6 mass % or less, and more preferably0.2 mass % or less. This makes it possible to adjust the amount of thepolymerizable compound contained in the ultraviolet ray curable inkcomposition to a relatively high value. Therefore, it is possible toespecially improve the wear resistance and the like of the printedportion to be formed using the ultraviolet ray curable ink composition.Further, in the invention, even in the case where the amount of thepolymerization inhibitor is relatively lower in such a way, it ispossible to make the storage stability and the ejection stability of theultraviolet ray curable ink composition sufficiently excellent.

Further, it is preferred that the ultraviolet ray curable inkcomposition of the invention contains no organic solvent to be removed(evaporated) in the processes of producing the printed object. Thismakes it possible to efficiently prevent an issue of a volatile organiccompound (VOC) from generating.

A viscosity at room temperature (20° C.) of the ultraviolet ray curableink composition of the invention is preferably 20 mPa·s or less, andmore preferably in the range of 3 mPa·s or more but 15 mPa·s or less.This makes it possible to appropriately eject the ultraviolet raycurable ink composition using the ink jet method.

Printed Object

Next, a printed object of the invention will be described.

The printed object of the invention is produced by applying the abovementioned ultraviolet ray curable ink composition onto the recordingmedium, and then irradiating the ultraviolet ray curable ink compositionwith an ultraviolet ray. Such a printed object is provided with apattern (printed portion) having high gloss and wear resistance.

As described above, the ultraviolet ray curable ink compositionaccording to the invention contains the predetermined polymerizablecompound, and thus exhibits excellent adhesion with respect to therecording medium. Therefore, since the ultraviolet ray curable inkcomposition of the invention exhibits the excellent adhesion withrespect to the recording medium, the recording medium may be any types.As the recording medium, an absorbent medium or an unabsorbent mediummay be used. For example, a paper (e.g., a plain paper, a special paperfor ink jet), a plastic material, a metal, a ceramics, a timber, ashell, a natural or synthetic fiber such as cotton, polyester or wool, anon-woven fabric or the like can be used.

The printed object of the invention may be used in any applications, forexample, may be used in trinkets or articles other than the trinkets.Concrete examples of the printed object of the invention include:vehicular interior trims such as a console lid, a switch base, a centercluster, an interior panel, an emblem, a center console and meternameplate; operating portions of various kinds of electronic devices(keyswitchs); trims exhibiting decorativeness; presentments such as anindex and a logo; and the like.

As a system for ejecting liquid droplets (that is, a system of the inkjet method), a piezo system, a system for ejecting an ink by bubbleswhich are generated by heating the ink, or the like can be used.However, the piezo system is preferable, for the reason that theultraviolet ray curable ink composition is difficult to be deteriorated,and the other reasons.

The ejection of the ultraviolet ray curable ink composition by the inkjet method can be carried out by using a well-known liquid dropletejection device.

The ultraviolet ray curable ink composition ejected by the ink jetmethod is cured by being irradiated with the ultraviolet ray.

As an ultraviolet ray irradiation source, for example, a mercury lamp, ametal halide lamp, an ultraviolet ray light emitting diode (UV-LED), anultraviolet ray laser diode (UV-LD) or the like can be used. Among them,the ultraviolet ray light emitting diode (UV-LED) or the ultraviolet raylaser diode (UV-LD) is preferable, for the reasons that such a sourcehas a small size, a long life time, high efficiency and a low cost.

While the invention has been described hereinabove based on thepreferred embodiments, the invention is not limited thereto.

EXAMPLES

Next, description will be made on concrete examples of the invention.

1. Production of Ink Jet Composition Ultraviolet Ray Curable InkComposition Example 1

First, prepared was a film having a flat surface and made ofpolyethylene terephthalate (surface roughness Ra: 0.02 μm or less).

Next, silicone oil was applied onto the entirety of one surface of thefilm.

Next, a coat made of Al was formed onto a surface of the film on whichthe silicone oil was applied using an evaporation method.

The film (base) made of polyethylene terephthalate, on which the Al coatwas formed, was dipped into a liquid constituted of diethylene glycoldiethyl ether, and then ultrasonic vibration was applied thereto. Inthis way, obtained was a dispersion liquid of scaly particles (that is,particles to be used as base particles) each made of Al.

Next, CF₃(CF₂)₅(CH₂)₂O(P)(OH)₂ as the fluorine type phosphoric acidester was added into the dispersion liquid of the particles made of Alobtained as above so that a concentration thereof became 1 mass % toobtain a mixture. The mixture was stirred at a temperature of 45° C. for120 minutes to subject a surface treatment with a fluorine typephosphoric acid ester, thereby obtaining a metal powder dispersionliquid. The metal powder dispersion liquid was filtered and dried toobtain metal powder.

Thus obtained metal particles of the metal powder had an averageparticle size of 0.8 μm and an average thickness of 60 nm (because eachparticle was formed in scaly shape).

Next, the metal powder was mixed with γ-butyrolactone acrylate as amonomer having an alicyclic structure (polymerizable compound), phenoxyethyl acrylate as a monomer having no alicyclic structure (polymerizablecompound), Irgacure 819 (produced by BASF Japan Ltd.) as aphotopolymerization initiator, Speedcure TPO (produced by ACETO) as aphotopolymerization initiator, Speedcure DETX (produced by LambsonLimited) as a photopolymerization initiator, and a substance A having achemical structure represented by the following formula (6). By doingso, obtained was an ink jet composition (ultraviolet ray curable inkcomposition).

Examples 2 to 19

In each of the Examples 2 to 19, an ink jet composition (ultraviolet raycurable ink composition) was produced in the same manner as the Example1, except that a constitution (composition of each base particle and akind of compound used for the surface treatment (fluorine typecompound)) of the metal particles was changed as shown in Tables 1 and2, and the kinds and ratio of the raw materials used for preparing theink jet composition (ultraviolet ray curable ink composition) werechanged as shown in Tables 1 and 2.

Comparative Example 1

An ink jet composition (ultraviolet ray curable ink composition) wasproduced in the same manner as Example 1, except that particles eachmade of Al and not subjected to the surface treatment were used as themetal particles of the metal powder.

Comparative Example 2

An ink jet composition (ultraviolet ray curable ink composition) wasproduced in the same manner as Example 1, except that spherical Alparticles produced by using a gas atomizing method (not subjected to thesurface treatment) were used as the metal particles of the metal powder.

Comparative Example 3

An ink jet composition (ultraviolet ray curable ink composition) wasproduced in the same manner as Example 1, except thatNH₃—(CH₂)₃—Si(OCH₃)₃, which was not the fluorine type silane compoundand the fluorine phosphoric acid ester, was used instead ofCF₃(CF₂)₅(CH₂)₂O(P)(OH)₂ as the fluorine phosphoric acid ester, andsubjected to the surface treatment to obtain the metal particles of themetal powder.

Comparative Examples 4 to 6

In each of the Comparative Examples 6 to 9, an ink jet composition(ultraviolet ray curable ink composition) was produced in the samemanner as Example 1, except that the monomer having the alicyclicstructure was not used as polymerizable compound, and the kinds andratio of the raw materials used for preparing the ink jet composition(ultraviolet ray curable ink composition) were changed as shown in Table2.

The constitutions of the ink jet compositions obtained in the Examplesand the Comparative Examples were shown in Table 1 and Table 2 as awhole. In Tables, indicated were CF₃(CF₂)₅(CH₂)₂O(P)(OH)₂ as “S1”,CF₃(CF₂)₅(CH₂)₂O(P)(OH)(OCH₂CH₃) as “S2”, CF₃(CF₂)₄(CH₂)₂O—PO(OH)₂ as“S3”, CF₃(CF₂)₅—CH₂CH₂—Si(OC₂H₅)₃ as “S4”, CF₃—CH₂CH₂—Si(OCH₃)₃ as “S5”,CF₃(CF₂)₇—CH₂CH₂—Si(OCH₃)₃ as “S6”, CF₃(CF₂)₅(CH₂)₂O—PO(OH)(OC₂H₅) as“S7”, CF₃(CF₂)₅—CH₂CH₂—Si(OCH₃)₃ as “S8”, NH₃—(CH₂)₃—Si(OCH₃)₃—Si(OCH₃)₃as “S′1”, γ-butyrolactone acrylate as the monomer having the alicyclicstructure (polymerizable compound) as “BLA”, tetrahydrofurfuryl acrylateas the monomer having the alicyclic structure (polymerizable compound)as “THFA”, N-vinyl caprolactam as the monomer having the alicyclicstructure (polymerizable compound) as “VC”, N-vinyl pyrolidone as themonomer having the alicyclic structure (polymerizable compound) as “VP”,acryloyl morpholine as the monomer having the alicyclic structure(polymerizable compound) as “AMO”, tris(2-acryloyloxy ethyl)isocyanurate as the monomer having the alicyclic structure(polymerizable compound) as “TAOEI”, dicyclopentenyl oxyethyl acrylateas the monomer having the alicyclic structure (polymerizable compound)as “DCPTeOEA”, adamantyl acrylate as the monomer having the alicyclicstructure (polymerizable compound) as “AA”, dimethylol tricyclodecanediacrylate as the monomer having the alicyclic structure (polymerizablecompound) as “DMTCDDA”, dimethylol dicyclopentane diacrylate as themonomer having the alicyclic structure (polymerizable compound) as“DMDCPTA”, dicyclopentenyl acrylate as the monomer having the alicyclicstructure (polymerizable compound) as “DCPTeA”, dicyclopentanyl acrylateas the monomer having the alicyclic structure (polymerizable compound)as “DCPTaA”, isobornyl acrylate as the monomer having the alicyclicstructure (polymerizable compound) as “IBA”, cyclohexyl acrylate as themonomer having the alicyclic structure (polymerizable compound) as“CHA”, diacrylated isocyanurate as the monomer having the alicyclicstructure (polymerizable compound) as “DAI”, triacrylated isocyanurateas the monomer having the alicyclic structure (polymerizable compound)as “TAI”, γ-butyrolactone methacrylate as the monomer having thealicyclic structure (polymerizable compound) as “BLM”,tetrahydrofurfuryl methacrylate as the monomer having the alicyclicstructure (polymerizable compound) as “THFM”, dicyclopentenyl oxyethylmethacrylate as the monomer having the alicyclic structure(polymerizable compound) as “DCPTeOEM”, adamantyl methaacrylate as themonomer having the alicyclic structure (polymerizable compound) as “AM”,pentamethyl piperidyl methacrylate as the monomer having the alicyclicstructure (polymerizable compound) as “PMPM”, tetramethyl piperidylmethacrylate as the monomer having the alicyclic structure(polymerizable compound) as “TMPM”, 2-methyl-2-adamantyl methacrylate asthe monomer having the alicyclic structure (polymerizable compound) as“MAM”, 2-ethyl-2-adamantyl methacrylate as the monomer having thealicyclic structure (polymerizable compound) as “EAM”, mevalonic acidlactone methacrylate as the monomer having the alicyclic structure(polymerizable compound) as “MLM”, dicyclopentenyl methacrylate as themonomer having the alicyclic structure (polymerizable compound) as“DCPTeM”, dicyclopentanyl methacrylate as the monomer having thealicyclic structure (polymerizable compound) as “DCPTaM”, isobornylmethacrylate as the monomer having the alicyclic structure(polymerizable compound) as “IBM”, cyclohexyl methacrylate as themonomer having the alicyclic structure (polymerizable compound) as“CHM”, phenoxy ethyl acrylate as the monomer having no alicyclicstructure (polymerizable compound) as “PEA”, dipropylene glycoldiacrylate as the monomer having no alicyclic structure (polymerizablecompound) as “DPGDA”, tripropylene glycol diacrylate as the monomerhaving no alicyclic structure (polymerizable compound) as “TPGDA”,2-hydroxy-3-phenoxy propyl acrylate as the monomer having no alicyclicstructure (polymerizable compound) as “HPPA”, 4-hydroxy butyl acrylateas the monomer having no alicyclic structure (polymerizable compound) as“HBA”, ethyl carbitol acrylate as the monomer having no alicyclicstructure (polymerizable compound) as “ECA”, methoxy triethylene glycolacrylate as the monomer having no alicyclic structure (polymerizablecompound) as “MTEGA”, t-butyl acrylate as the monomer having noalicyclic structure (polymerizable compound) as “TBA”, benzyl acrylateas the monomer having no alicyclic structure (polymerizable compound) as“BA”, 2-(2-hydroxy ethoxy) ethyl acrylate as the monomer having noalicyclic structure (polymerizable compound) as “VEER”, benzylmethacrylate as the monomer having no alicyclic structure (polymerizablecompound) as “BM”, urethane acrylate as the monomer having no alicyclicstructure (polymerizable compound) as “UA”, DISPERBYK-182 (produced byBYK Japan KK, an amine number is 13 mgKOH/g) as “D2”, DISPERBYK-2155(produced by BYK Japan KK, an amine number is mgKOH/g) as “D5”, acompound represented by the above formula (6) (that is, the substance A)as “A1”, a compound represented by the following formula (7) (that is,the substance A) as “A2”, a compound represented by the followingformula (8) (that is, the substance A) as “A3”, a compound representedby the following formula (9) (that is, the substance A) as “A4”,Irgacure 819 (produced by BASF Japan Ltd.) as “ic819”, Speedcure TPO(produced by ACETO) as “scTPO”, Speedcure DETX (produced by LambsonLimited) as “scDETX”, UV-3500 (produced by BYK Japan KK) as “UV3500”,hydroquinone monomethyl ether as “MEHQ”, LHP-96 (produced by kusumotoChemicals, Ltd.) as “LHP”, and LF-1984 (produced by kusumoto Chemicals,Ltd.) as “LF”. Furthermore, in the composition of the constituentmaterial of the base particles in the Example 15 of Table 2, an amountof each element was shown in a ratio by weight. Furthermore, arbitrary10 particles contained in each ink jet composition were observed. Ineach of the particles, an area of the particle observed from a directionwhere a project area thereof becomes maximum (that is, an area of eachparticle at a planar view thereof) is defined as S₁ (μm²) and an area ofthe particle observed from a direction where the area of the particleobserved from directions orthogonal to the above observation directionbecomes maximum is defined as S₀ (μm²), and a ratio of S₁ to S₀ (S₁/S₀)was calculated to obtain 10 values. An average of the calculated 10values was indicated in Table 1 and Table 2 as a whole. Moreover, aviscosity at 20° C. of the ink jet composition (ultraviolet ray curableink composition) obtained in each of the Examples, which was measured byusing an oscillating type viscometer based on JIS 28809, was a valuefalling within the range of 3 mPa·s or more but 15 mPa·s or less. Inthis regard, it is to be noted that each of D2 and D5 had the basicproperty and the polymer structure (basic polymer dispersant).

where the substance A represented by the formula (9) is a mixture of aplurality of compounds in which “n” in the formula is 10 or more but 19or less (main components are compounds in which “n” in the formula is 15or more but 18 or less).

TABLE 1 Table 1 Constitution of metal powder Constitution of ink jetcomposition Constituent Material used Metal particles of metal powderPolymerizable compound material of for surface Average particle AmountAmount base particles treatment Shape size [μm] S₁/S₀ [mass %] Kind[mass %] Ex. 1 Al S1 Scaly 0.8 23 2.0 BLA/PEA 60.0/27.8 Ex. 2 Al S2Scaly 0.9 25 4.0 BLA/THFA 41.5/43.3 Ex. 3 Al S1 + S2 Scaly 2.0 51 2.0VC/VP/ 25.8/32.1/ AMO/VEEA 17.5/9.6 Ex. 4 Al S3 Scaly 1.0 29 2.0BLM/THFM/ 7.4/5.1/ TAOEI/DCPTeOEA/ 31.0/32.0/ AA/PEA/DPGDA 5.5/4.0/3.9Ex. 5 Al S5 Scaly 0.9 24 2.0 AM/PMPM/TMPM/ 3.9/7.9/3.0/ MAM/EAM/DCPTeA/3.0/3.1/59.1/ PEA/TPGDA/VEEA 3.2/1.2/2.0 Ex. 6 Al S7 Scaly 0.8 23 2.0DCPTeOEM/MLM/ 3.8/3.6/ DMTCDDA/DCPTaA/ 19.6/29.1/ 1BA/CHM/PEA/HPPA9.6/9.4/6.5/5.0 Ex. 7 Al S1 Scaly 0.8 23 2.0 DMDCPTA/DCPTeM/ 45.42/5.5/DCPTaM/IBM/CHA/ 6.6/5.9/17.8/ PEA/HBA/VEEA 4.1/1.1/1.0 Ex. 8 Al S1 + S2Scaly 0.9 25 4.0 BLA/THFA/ 29.1/34.0/ PEA/HBA/AMO 9.5/9.0/3.2 Ex. 9 AlS2 Scaly 2.0 51 2.0 BLA/THFA/ 25.2/32.7/ VC/PEA 7.2/19.9 Ex. 10 Al S4Scaly 1.1 28 2.0 BLA/THFA/ 26.6/23.5/ TBA/VEEA/UA 15.0/9.5/12.6 Ex. 11Al S5 Scaly 1.0 29 2.0 BLA/THFA/ 33.5/34.9/ VP/PEA 3.5/16.9 Ex. 12 Al S6Scaly 0.7 19 4.0 BLA/THFA/ 24.9/23.9/ VEEA/BM/UA 14.1/16.1/10.2Constitution of ink jet composition Dispersant Substance A Othercomponents Amount Amount Amount Kind [mass %] Kind [mass %] Kind [mass%] Ex. 1 — — A1 0.2 ic819/scTPO/scDETX 4.0/4.0/2.0 Ex. 2 — — A2 0.8ic819/scTPO/ 4.0/4.0/ scDETX/UV3500/MEHQ 2.0/0.2/0.2 Ex. 3 D2 1.4 A1 1.4ic819/scTPO/ 4.0/4.0/ scDETX/UV3500 2.0/0.2 Ex. 4 — — A3 0.7ic819/scTPO/ 4.0/4.0/ UV3500/MEHQ 0.2/0.2 Ex. 5 — — A4 1.2 ic819/scTPO/4.0/4.0/ scDETX/UV3500/MEHQ 2.0/0.2/0.2 Ex. 6 — — A1 1.0 ic819/scTPO/4.0/4.0/ scDETX/UV3500/MEHQ 2.0/0.2/0.2 Ex. 7 — — A1 0.58 ic819/scTPO/4.0/4.0/2.0 scDETX Ex. 8 — — A2 0.8 ic819/scTPO/ 4.0/4.0/scDETX/UV3500/MEHQ 2.0/0.2/0.2 Ex. 9 D2 1.4 A1 1.4 ic819/scTPO/ 4.0/4.0/scDETX/LF 2.0/0.2 Ex. 10 — — A1 0.4 ic819/scTPO/ 4.0/4.0/scDETX/UV3500/MEHQ 2.0/0.2/0.2 Ex. 11 — — A3 0.8 ic819/scTPO/ 4.0/4.0/UV3500/MEHQ 0.2/0.2 Ex. 12 D5 0.2 A1 0.2 ic819/scTPO/ 4.0/2.0/UV3500/MEHQ 0.2/0.2

TABLE 2 Table 2 Constitution of metal powder Constitution of ink jetcomposition Constituent Material used Metal particles of metal powderPolymerizable compound material of for surface Average particle AmountAmount base particles treatment Shape size [μm] S₁/S₀ [mass %] Kind[mass %] Ex. 13 Al S7 Scaly 0.9 39 2.0 BLA/THFA/ 32.0/34.1/ PEA 20.3 Ex.14 Al S8 Scaly 1.5 47 1.0 DAI/TAI/ 20.8/20.0/ ECA/MTEGA/ 18.1/17.2/IBA/BA 6.0/5.5 Ex. 15 Ni49.5Fe50.5 S6 Scaly 1.8 39 2.0 BLA/THFA/27.0/26.5/ TBA/VEEA/UA 13.8/15.5/4.0 Ex. 16 SUS316L S7 Scaly 1.5 23 2.0BLA/THFA/ 26.2/27.6/ VEEA/BM/UA 14.1/15.5/4.0 Ex. 17 Al S3 + S4 Scaly0.8 25 2.0 BLA/THFA/ 30.8/34.1/ PEA 20.7 Ex. 18 Al S1 Scaly 0.9 25 1.5AMO/THFA 43.7/43.3 Ex. 19 Al S2 Scaly 0.9 23 1.2 AMO/THFA/PEA40.0/40.0/7.0 Com. Ex. 1 Al — Scaly 0.8 1 2.0 BLA/PEA 60.0/27.8 Com. Ex.2 Al — Spherical 0.8 23 2.0 BLA/PEA 60.0/27.8 Com. Ex. 3 Al S′ 1 Scaly0.8 23 2.0 BLA/PEA 60.0/27.8 Com. Ex. 4 Al S1 Scaly 0.8 23 2.0 BLA 87.8Com. Ex. 5 Al S1 Scaly 0.8 23 2.0 BLA 81.8 Com. Ex. 6 Al S1 Scaly 0.8 232.0 BLA 81.8 Constitution of ink jet composition Dispersant Substance AOther components Amount Amount Amount Kind [mass %] Kind [mass %] Kind[mass %] Ex. 13 — — A4 1.2 ic819/scTPO/ 4.0/4.0/ scDETX/UV3500/MEHQ2.0/0.2/0.2 Ex. 14 — — A1 1.0 ic819/scTPO/ 4.0/4.0/ scDETX/UV3500/MEHQ2.0/0.2/0.2 Ex. 15 — — A2 0.8 ic819/scTPO/ 4.0/4.0/ scDETX/UV3500/MEHQ2.0/0.2/0.2 Ex. 16 D5 0.2 A1 0.2 ic819/scTPO/ 4.0/4.0/ scDETX/LHP2.0/0.2 Ex. 17 D2 1.0 A1 1.0 ic819/scTPO/ 4.0/4.0/ scDETX/UV3500/MEHQ2.0/0.2/0.2 Ex. 18 — — A2 0.3 ic819/scTPO/ 4.0/4.0/ scDETX/LHP/LF2.0/0.2/0.2 Ex. 19 — — A2 0.6 ic819/scTPO/ 4.0/4.0/ scDETX/UV3500/MEHQ2.0/0.2/0.2 Com. Ex. 1 — — A1 0.2 ic819/scTPO/ 4.0/4.0/2.0 scDETX Com.Ex. 2 — — A1 0.2 ic819/scTPO/ 4.0/4.0/2.0 scDETX Com. Ex. 3 — — A1 0.2ic819/scTPO/ 4.0/4.0/2.0 scDETX Com. Ex. 4 — — A1 0.2 ic819/scTPO/4.0/4.0/2.0 scDETX Com. Ex. 5 D2 6.0 A1 0.2 ic819/scTPO/ 4.0/4.0/2.0scDETX Com. Ex. 6 D5 6.0 A1 0.2 ic819/scTPO/ 4.0/4.0/2.0 scDETX

2. Evaluation of Stability of Liquid Droplet Ejection Ejection StabilityEvaluation

The ink jet composition prepared in each of the Examples and theComparative Examples was evaluated by tests as described below.

First, a liquid droplet ejection device provided inside a chamber(thermal chamber) and the ink jet composition obtained in each of theExamples and the Comparative Examples were prepared. Driving waveformsof piezo elements were optimized, and then 2,000,000 liquid droplets ofthe ink jet composition were continuously ejected from the respectivenozzles of the liquid droplet ejection head under the environment of 25°C. and 55% RH. Thereafter, operation of the liquid droplet ejectiondevice was stopped, and then was left for 360 hours under theenvironment of 25° C. and 55% RH in a state that the ink jet compositionwas filled into flow passes of the liquid droplet ejection device.

Next, 4,000,000 liquid droplets of the ink jet composition werecontinuously ejected from the respective nozzles of the ink jet headunder the environment of 25° C. and 55% RH. On each of 4,000,000 liquiddroplets ejected from the specified nozzles located at the vicinity of acentral portion of the liquid droplet ejection head after a lapse of3600 hours, a shift length “d” between a center point of the spotted(landed) droplet and an objective point thereof to be spotted wasmeasured. An average value of the shift lengths “d” was calculated.Based on the calculated average value, the stability of liquid dropletejection was evaluated according to the following criteria including 5grades. In this regard, it is to be noted that a smaller average valuemeans that change of an ejecting direction of each liquid droplet iseffectively prevented.

A: The average value of the shift lengths “d” is less than 0.07 μm.

B: The average value of the shift lengths “d” is 0.07 μm or more, butless than 0.14 μm.

C: The average value of the shift lengths “d” is 0.14 μm or more, butless than 0.17 μm.

D: The average value of the shift lengths “d” is 0.17 μm or more, butless than 0.21 μm.

E: The average value of the shift lengths “d” is 0.21 μm or more.

3. Frequency Characteristic of Ink Jet Composition

A liquid droplet ejection device provided inside a chamber (thermalchamber) and the ink jet composition obtained in each of the Examplesand the Comparative Examples were prepared. Driving waveforms of piezoelements were optimized, and then the liquid droplets of the ink jetcomposition were ejected from all of the nozzles of the liquid dropletejection head under the environment of 25° C. and 55% RH while changinga number of vibration (frequency) of the piezo elements. The time forejecting the liquid droplets in each frequency was set to 20 minutes. Atthe time of completing the ejection for 20 minutes, frequencies in whicha number of nozzles, which have not been ejected, was less than 1% withrespect to all of the nozzles were set as a practicable maximumfrequency. Thereafter, practicable frequencies were evaluated accordingto the following criteria including 4 grades in a frequency range. Inthis regard, it is to be noted that a larger value means that thefrequency characteristic of each liquid droplet is excellent.

A: The frequency is 15 kHz or more.

B: The frequency is 10 kHz or more, but less than 15 kHz.

C: The frequency is 5 kHz or more, but less than 10 kHz.

D: The frequency is less than 5 kHz.

4. Evaluation of Storage Stability of Ink Jet Composition Long-TermStability Evaluation

4.1. Dispersibility

The ink jet composition obtained in each of the Examples and theComparative Examples was left for 60 days under the environment of 40°C. Then, the ink jet composition of 1 L was passed through a capsulefilter having filtration accuracy of 3 μm (produced by YAMASHIN-FILTERDORP.). At this time, concentrations of the ink in the ink jetcomposition were measured before and after the pass. Then, the loss ofthe ink jet composition by filtering coarse particles due to dispersiondeficiency is obtained as a decreasing ratio of the concentration of theink. Thereafter, the storage stability was evaluated according to thefollowing criteria including 4 grades.

A: The decreasing ratio of the concentration of the ink is less than 5%.

B: The decreasing ratio of the concentration of the ink is 5% or more,but less than 10%.

C: The decreasing ratio of the concentration of the ink is 10% or more,but less than 20%.

D: The decreasing ratio of the concentration of the ink is 20% or more,but less than 40%.

4.2 Increasing Ratio of Viscosity

The ink jet composition prepared in each of the Examples and theComparative Examples was left for 60 days under the environment of 40°C. Thereafter, the viscosity at 20° C. of the ink jet compositionobtained in each of the Examples and the Comparative Examples wasmeasured using an oscillating type viscometer based on JIS 28809, andthen an increasing ratio with respect to the viscosity of the ink jetcomposition just after prepared was calculated. Based on the increasingratio of the viscosity, the storage stability was evaluated according tothe following criteria including 5 grades.

A: The increasing ratio of the viscosity is less than 5%.

B: The increasing ratio of the viscosity is 5% or more, but less than10%.

C: The increasing ratio of the viscosity is 10% or more, but less than18%.

D: The increasing ratio of the viscosity is 18% or more, but less than23%.

E: The increasing ratio of the viscosity is 23% or more, or generationof foreign materials is observed.

5. Curing Property

The ink jet composition prepared in each of the Examples and theComparative Examples was loaded to an ink jet printer (“PM800C” producedby Seiko Epson Corporation), solid printing of the ink jet compositiononto a recording medium having a thickness of 38 μm (“DIAFOIL G440E”produced by Mitsubishi Plastics Inc.) was carried out in an ink amountof 9 g/m² in wet, and then the ink jet composition was immediatelyirradiated with an ultraviolet ray (gap: 6 mm, peak wavelength: 365 nm,1000 mW/cm²) using a LED-UV lump (“RX firefly” produced by PhoseonTechnology Inc.). Thereafter, it was confirmed whether or not the inkjet composition was cured. Based on the confirmation result, the curingproperty was evaluated according to the following criteria including 5grades. The curing or non-curing of the ink jet composition was judgedby rubbing a surface of the ink jet composition with a swab andobserving whether or not a non-cured matter of the ink jet compositionadhered to the swab. In this regard, it is to be noted that anultraviolet ray irradiation amount in the followings A to E can becalculated by the number of seconds when the LED-UV lump was lighted.

A: The ink jet composition was cured by the ultraviolet ray irradiationamount less than 100 mJ/cm².

B: The ink jet composition was cured by the ultraviolet ray irradiationamount of 100 mJ/cm² or more, but less than 200 mJ/cm².

C: The ink jet composition was cured by the ultraviolet ray irradiationamount of 200 mJ/cm² or more, but less than 500 mJ/cm².

D: The ink jet composition was cured by the ultraviolet ray irradiationamount of 500 mJ/cm² or more, but less than 1,000 mJ/cm².

E: The ink jet composition was cured by the ultraviolet ray irradiationamount of 1,000 mJ/cm² or more, or was never cured.

6. Production of Printed Object

An interior panel as a printed object was produced by using the ink jetcomposition prepared in each of the Examples and the ComparativeExamples as follows.

First, the ink jet composition was loaded to an ink jet device.

Next, on a base material (recording medium) having a curved surfaceportion, which was formed using a polycarbonate sheet with a thicknessof 2 mm (“CARBOGLASS polish” produced by ASAHI GLASS CO., LTD.), the inkjet composition was ejected in a predetermined pattern.

Thereafter, the ink jet composition was irradiated with an ultravioletray having a spectrum with maximum values at wavelengths of 365 nm, 380nm and 395 nm and an irradiation intensity of 160 mW/cm² for 10 seconds,and thus was cured. In this way, the interior panel was produced as theprinted object.

In each of the Examples and the Comparative Examples, 10 interior panels(printed objects) were produced using the ink jet composition accordingto the above mentioned method.

Further, 10 interior panels (printed objects) were produced by using theink jet composition prepared in each of the Examples and the ComparativeExamples in the same method as described above, except that a basematerial formed by using a polyethylene terephthalate sheet with athickness of 38 μm (“DIAFOIL G440E” produced by Mitsubishi PlasticsInc.), a base material formed by using a low density polyethylene sheet(“T.U.X (L-LDPE) HC-E #80” produced by Mitsui Chemicals Tohcello Inc.),a base material formed by using a biaxial stretching polypropylene sheet(“OP U-1 #60” produced by Mitsui Chemicals Tohcello Inc.), and a basematerial formed by using a hard vinyl chloride sheet having a thicknessof 0.5 mm (“SUNDAY SHEET (transparent)” produced by ACRYSUNDAY Co.,Ltd.) were used.

7. Evaluation of Printed Object

Each of the printed objects produced in the above mentioned way wasevaluated as follows.

7.1 Evaluation of Appearance of Printed Object

The printed objects produced by using the ink jet composition preparedin each of the Examples and the Comparative Examples were visuallyobserved, and appearance of each of the printed objects was evaluatedaccording to the following criteria including 7 grades.

A: The printed object exhibits gloss with very high-grade sense, and hasextra excellent appearance.

B: The printed object exhibits gloss with very high-grade sense, and hasvery excellent appearance.

C: The printed object exhibits gloss with high-grade sense, and hasexcellent appearance.

D: The printed object exhibits gloss with high-grade sense, and hasappropriate appearance.

E: The printed object exhibits inferior gloss, and has slightly poorappearance.

F: The printed object exhibits inferior gloss, and has poor appearance.

G: The printed object exhibits inferior gloss, and has extra poorappearance.

7.2 Glossiness

Glossiness of pattern formation portion of the printed object producedby using the ink jet composition prepared in each of the Examples andthe Comparative Examples was measured at a measurement angle of 60°using a gloss meter (“MINOLTA MULTI GLOSS 268”), and the glossiness wasevaluated according to the following criteria including 4 grades.

A: The glossiness is 400 or more.

B: The glossiness is 300 or more, but less than 400.

C: The glossiness is 200 or more, but less than 300.

D: The glossiness is less than 200.

7.3 Wear Resistance

At 48 hours having passed since the production of the printed objectproduced by using the ink jet composition prepared in each of theExamples and the Comparative Examples, the printed object was subjectedto a wear resistance test using a Sutherland Rub Tester based on JISK5701. Such a wear resistance test was carried out by using a film madeof polyethylene terephthalate (“DIAFOIL G440E” produced by MitsubishiPlastics Inc.) as an interleaving paper. Thereafter, on the printedobjects after the wear resistance test, glossiness thereof was alsomeasured at the measurement angle of 60° in the same manner as describedin the above [7.2]. A decreasing ratio of the glossiness before andafter the wear resistance test was calculated, and then the wearresistance was evaluated according to the following criteria including 5grades.

A: The decreasing ratio of the glossiness is less than 5%.

B: The decreasing ratio of the glossiness is 5% or more, but less than13%.

C: The decreasing ratio of the glossiness is 13% or more, but less than23%.

D: The decreasing ratio of the glossiness is 23 or more, but less than27%.

E: The decreasing ratio of the glossiness is 27% or more, or theparticles are removed, so that the surface of the recording medium isexposed.

These results are indicated in Table 3. In this regard, in Table 3, itis to be noted that indicated are the printed object formed by using thebase material made of polycarbonate as “M1”, the printed object formedby using the base material made of polyethylene terephthalate as “M2”,the printed object formed by using the base material made of low densitypolyethylene as “M3”, the printed object formed by using the basematerial made of biaxial stretching polypropylene as “M4”, and theprinted object formed by using the base material made of hard vinylchloride as “M5”.

TABLE 3 Loag-term stability Appearance of Ejection Frequence Dispers-Viscos- Curing printed object Glossiness Wear resistance stabilitycharacteristic ibilily ity property M1 M2 M3 M4 M5 M1 M2 M3 H4 M5 M1 M2M3 M4 M5 Ex. 1 A A A A A A A A A A A A A A A A A A A A Ex. 2 A A A A A AA A A A A A A A A A A A A A Ex. 3 A A A A A A A A A A A A A A A A A A AA Ex. 4 A A A A A A A A A A A A A A A A A A A A Ex. 5 A A A A A A A A AA A A A A A A A A A A Ex. 6 A A A A A A A A A A A A A A A A A A A A Ex.7 A A A A A A A A A A A A A A A A A A A A Ex. 8 A A A A A A A A A A A AA A A A A A A A Ex. 9 A A A A A A A A A A A A A A A A A A A A Ex. 10 B AB B A A A A A A B B B B B A A A A A Ex. 11 A A A A A A A A A A A A A A AA A A A A Ex. 12 B A B B A A A A A A B B B B B A A A A A Ex. 13 A A A AA A A A A A A A A A A A A A A A Ex. 14 A A A A A A A A A A A A A A A A AA A A Ex. 15 B B A A A A A A A A B B B B B A A A A A Ex. 16 B B A A A AA A A A B B B B B A A A A A Ex. 17 A A A A A A A A A A A A A A A A A A AA Ex. 18 A A A A A A A A A A A A A A A A A A A A Ex. 19 A A A A A A A AA A A A A A A A A A A A Com. E D D E A F F F F F C C C C C C C C C C Ex.1 Com. D C D D A G G G G G D D D D D C C C C C Ex. 2 Com. C B C C A E EE E E C C C C C C C C C C Ex. 3 Com. E D D E A D D D D D C C C C C C C CC C Ex. 4 Com. C C B C A G G G G G D D D D D C C C C C Ex. 5 Com. C C BC A G G G G G D D D D D C C C C C Ex. 6

As clearly shown in Table 3, the ultraviolet ray curable ink compositionof the invention is excellent in the liquid droplet ejection stability,the storage stability and the curing property. Further, the printedobject of the invention exhibits superior gloss and has excellentappearance, and the pattern formation portion also has high wearresistance. Further, by using the ultraviolet ray curable inkcomposition of the invention, excellent results were obtained stablywithout the dependency of the kind of recording medium. In contrast,sufficient results are not obtained in Comparative Examples.

What is claimed is:
 1. An ultraviolet ray curable ink compositionadapted to be ejected by using an ink jet method, comprising: apolymerizable compound; metal powder; and wherein the metal powder isconstituted from metal particles subjected to a surface treatment with afluorine type silane compound and/or a fluorine type phosphoric acidester as a surface treatment agent, and wherein the polymerizablecompound includes a monomer having an alicyclic structure.
 2. Theultraviolet ray curable ink composition as claimed in claim 1, whereinan amount of the monomer having the alicyclic structure contained in theultraviolet ray curable ink composition is in the range of 40 mass % ormore but 90 mass % or less.
 3. The ultraviolet ray curable inkcomposition as claimed in claim 1, wherein each of the metal particlesof the metal powder is constituted from a base particle and Alconstituting at least a surface of the base particle, and the metalparticle is subjected to the surface treatment with the fluorine typesilane compound and/or the fluorine type phosphoric acid ester.
 4. Theultraviolet ray curable ink composition as claimed in claim 1, whereineach of the metal particles of the metal powder is of a scaly shape. 5.The ultraviolet ray curable ink composition as claimed in claim 1,wherein when the metal particles of the metal powder are subjected tothe surface treatment with the fluorine type silane compound, thefluorine type silane compound has a chemical structure represented bythe following formula (1):R¹SiX¹ _(a)R² _((3−a))  (1) where in the above formula (1), “R¹”represents a hydrocarbon group in which a part or all of hydrogen atomsare substituted with fluorine atoms, “X¹” represents a hydrolysis group,an ether group, a chloro group or a hydroxyl group, “R²” represents analkyl group having a carbon number in the range of 1 or more but 4 orless, and “a” is an integral number in the range of 1 or more but 3 orless.
 6. The ultraviolet ray curable ink composition as claimed in claim1, wherein when the metal particles of the metal powder are subjected tothe surface treatment with the fluorine type phosphoric acid ester, thefluorine type phosphoric acid ester has a chemical structure representedby the following formula (2):POR_(n)(OH)_(3−n)  (2) where in the above formula (2), “R” isCF₃(CF₂)_(m)—, CF₃(CF₂)_(m)(CH₂)_(l)—, CF₃(CF₂)_(m)(CH₂O)_(l)—,CF₃(CF₂)_(m)(CH₂CH₂O)_(l)—, CF₃(CF₂)_(m)O— or CF₃(CF₂)_(m)(CH₂)_(l)O—,“n” is an integral number in the range of 1 or more but 3 or less, “m”is an integral number in the range of 5 or more but 17 or less, and “l”is an integral number in the range of 1 or more but 12 or less.
 7. Theultraviolet ray curable ink composition as claimed in claim 1, whereinwhen the metal particles of the metal powder are subjected to thesurface treatment with the fluorine type phosphoric acid ester, thefluorine type phosphoric acid ester is represented byCF₃(CF₂)₅(CH₂)₂O(P)(OH)₂ and/or CF₃(CF₂)₅(CH₂)₂O(P)(OH)(OCH₂CH₃).
 8. Theultraviolet ray curable ink composition as claimed in claim 1, whereinan average particle size of the metal particles of the metal powder isin the range of 500 nm or more but 3.0 μm or less.
 9. The ultravioletray curable ink composition as claimed in claim 1, wherein the monomerhaving the alicyclic structure includes a monofunctional monomer havinga hetero atom in the alicyclic structure.
 10. The ultraviolet raycurable ink composition as claimed in claim 9, wherein an amount of themonofunctional monomer contained in the ultraviolet ray curable inkcomposition is in the range of 10 mass % or more but 80 mass % or less.11. The ultraviolet ray curable ink composition as claimed in claim 1,wherein the monomer having the alicyclic structure includes one or moreselected from the group consisting of tris(2-acryloyloxy ethyl)isocyanurate, dicyclopentenyl oxyethyl acrylate, adamantyl acrylate,γ-butyrolactone acrylate, N-vinyl caprolactam, N-vinyl pyrrolidone,pentamethyl piperidyl acrylate, tetramethyl piperidyl acrylate,2-methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl acrylate, mevalonicacid lactone acrylate, dimethylol tricyclodecane diacrylate, dimethyloldicyclopentane diacrylate, dicyclopentenyl acrylate, dicyclopentanylacrylate, isobornyl acrylate, cyclohexyl acrylate, acryloyl morpholineand tetrahydrofurfuryl acrylate.
 12. The ultraviolet ray curable inkcomposition as claimed in claim 1, wherein the polymerizable compoundincludes one or more selected from the group consisting of phenoxy ethylacrylate, 2-(2-vinyloxy ethoxy) ethyl acrylate, dipropylene glycoldiacrylate, tripropylene glycol diacrylate, 2-hydroxy-3-phenoxy propylacrylate and 4-hydroxy butyl acrylate in other than the monomer havingthe alicyclic structure.
 13. The ultraviolet ray curable ink compositionas claimed in claim 1 further comprising a substance A having a partialstructure represented by the following formula (5),

where in the formula (5), “R¹” is an oxygen atom, a hydrogen atom, ahydrocarbon group or an alkoxyl group, and each of “R²”, “R³”, “R⁴” and“R⁵” is independently a hydrogen atom or a hydrocarbon group.
 14. Theultraviolet ray curable ink composition as claimed in claim 13, whereinwhen an amount of the substance A is defined as X_(A) mass % and anamount of the metal powder is defined as X_(M) mass %, the followingrelation is satisfied: 0.01≦X_(A)/X_(M)≦0.8.
 15. A printed objectproduced by applying the ultraviolet ray curable ink composition definedby claim 1 onto a recording medium, and then irradiating the ultravioletray curable ink composition with an ultraviolet ray.